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  • Convert date in text format to datetime format in T-SQL

    - by Rob
    I have a client supplied file that is loaded in to our SQL Server database. This file contains text based date values i.e. (05102010) and I need to read them from a db column and convert them to a normal date time value = '2010-05-10 00:00:00.000' as part of a clean-up process. Any guidance would be greatly appreciated.

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  • Show a number with specified number of significant digits

    - by dreeves
    I use the following function to convert a number to a string for display purposes (don't use scientific notation, don't use a trailing dot, round as specified): (* Show Number. Convert to string w/ no trailing dot. Round to the nearest r. *) Unprotect[Round]; Round[x_,0] := x; Protect[Round]; shn[x_, r_:0] := StringReplace[ ToString@NumberForm[Round[N@x,r], ExponentFunction->(Null&)], re@"\\.$"->""] (Note that re is an alias for RegularExpression.) That's been serving me well for years. But sometimes I don't want to specify the number of digits to round to, rather I want to specify a number of significant figures. For example, 123.456 should display as 123.5 but 0.00123456 should display as 0.001235. To get really fancy, I might want to specify significant digits both before and after the decimal point. For example, I might want .789 to display as 0.8 but 789.0 to display as 789 rather than 800. Do you have a handy utility function for this sort of thing, or suggestions for generalizing my function above? Related: Suppressing a trailing "." in numerical output from Mathematica

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  • Biased Random Number Generator

    - by cmptrer
    I am looking for a random number generator that can be biased. For instance, say I want a random number between 1-5, with the probability being: 1: Comes up 20% of the time 2: Comes up 10% of the time 3: Comes up 40% of the time 4: Comes up 25% of the time 5: Comes up 5% of the time Is there anything in the standard library, or other libraries out there that would do this? Alternatively, is there an efficient way to do this myself?

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  • How would I create a random number?

    - by Elliot Bonneville
    How would I create a random number using C++? I've heard that one should use the time as a seed, but I'm not sure how to do that with the correct syntax. How would I do this? One more thing - how would I limit the random number to a particular range? I'm simulating a dice roll and getting numbers in the millions...

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  • Extract number from string in MSBuild

    - by Ole Lynge
    I would like to extract the number from a string in MSBuild. How can I do that using the built in tasks or the MSBuild.Community.Tasks? (RegexMatch might do, but how?) Example: I have the string agent0076 and I would like to get out the number, without the leading zeros: 76

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  • Generating exactly prime number with Java

    - by Viet
    Hi, I'm aware of the function BigInteger.probablePrime(int bitLength, Random rnd) that outputs probably prime number of any bit length. I want a REAL prime number in Java. Is there any FOSS library to do so with acceptable performance? Thanks in advance!

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  • Insert lecture number and page number of lecture in footline

    - by Liam
    I am dividing a semester's worth of lectures via the \lecture command. I'd like to have in the footline (among other things) the lecture number, date, and page number of the current lecture. I would also like to use the default style footline, with the black box on the left and the blue on the right. So I define a lecture with e.g. \lecture{January 28, 2010}{lecture01} with \title[Lecture \insertlecturenumber{}(\insertlecture)\quad{}Page \insertframenumber]{Course Title} in the preamble, I get an error; it will not accept \insertlecture there. If I remove \insertlecture, it does what I want, except that the page number is counted from the start of the semester, not the lecture. Is there any way to do this? Thank you. Liam

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  • Rounding a positive number to a power of another number

    - by Sagekilla
    I'm trying to round a number to the next smallest power of another number. The number I'm trying to round is always positive. I'm not particular on which direction it rounds, but I prefer downwards if possible. I would like to be able to round towards arbitrary bases, but the ones I'm most concerned with at the moment is base 2 and fractional powers of 2 like 2^(1/2), 2^(1/4), and so forth. Here's my current algorithm for base 2. The log2 I multiply by is actually the inverse of log2: double roundBaseTwo(double x) { return 1.0 / (1 << (int)((log(x) * log2)) } Any help would be appreciated!

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  • convert javascript number to css value -- maximum number of trailing decimals

    - by philipp
    I am about to have some fun with the css transform matrix and javascript. At the moment everything is cool, except when a number becomes something like 0.000034e3344 after the to string conversion. Than the transform does not work. So I know that there is the Number.toFixed() method which actually solves the problem, but i ask myself how many trailing decimals make sense. So what is the highest value i can pass to the toFixed() method to get the most precise results? EDIT::: the exact number output was: 9.685539407532573e-20

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  • How to format the node_redis info function output?

    - by hh54188
    I want check the Redis info on my pc with node, so I use node_redis and run the info function: var redis = require("redis"), client = redis.createClient(); client.on("connect", function () { client.info(function (err, replay) { console.log(replay); }) }) but the response is un-format: `#Server\r\nredis_version:2.6.16\r\nredis_git_sha1:00000000\r\nredis_git_dirty:0\r\nredis_mode:standalone\r\nos:Linux 3.8.0-29-generic x86_64\r\narch_bits:64\r\nmultiplexing_api:epoll\r\ngcc_version:4.6.3\r\nprocess_id:2941\r\nrun_id:e60f261a6f4f6f081563a47961315eff6b1c005d\r\ntcp_port:6379\r\nuptime_in_seconds:1777\r\nuptime_in_days:0\r\nhz:10\r\nlru_clock:2040689\r\n\r\n# Clients\r\nconnected_clients:2\r\nclient_longest_output_list:0\r\nclient_biggest_input_buf:0\r\nblocked_clients:0\r\n\r\n# Memory\r\nused_memory:562584\r\nused_memory_human:549.40K\r\nused_memory_rss:2031616\r\nused_memory_peak:561784\r\nused_memory_peak_human:548.62K\r\nused_memory_lua:31744\r\nmem_fragmentation_ratio:3.61\r\nmem_allocator:jemalloc-3.2.0\r\n\r\n# Persistence\r\nloading:0\r\nrdb_changes_since_last_save:0\r\nrdb_bgsave_in_progress:0\r\nrdb_last_save_time:1383553917\r\nrdb_last_bgsave_status:ok\r\nrdb_last_bgsave_time_sec:-1\r\nrdb_current_bgsave_time_sec:-1\r\naof_enabled:0\r\naof_rewrite_in_progress:0\r\naof_rewrite_scheduled:0\r\naof_last_rewrite_time_sec:-1\r\naof_current_rewrite_time_sec:-1\r\naof_last_bgrewrite_status:ok\r\n\r\n# Stats\r\ntotal_connections_received:3\r\ntotal_commands_processed:5\r\ninstantaneous_ops_per_sec:0\r\nrejected_connections:0\r\nexpired_keys:0\r\nevicted_keys:0\r\nkeyspace_hits:0\r\nkeyspace_misses:0\r\npubsub_channels:0\r\npubsub_patterns:0\r\nlatest_fork_usec:0\r\n\r\n# Replication\r\nrole:master\r\nconnected_slaves:0\r\n\r\n# CPU\r\nused_cpu_sys:0.13\r\nused_cpu_user:0.19\r\nused_cpu_sys_children:0.00\r\nused_cpu_user_children:0.00\r\n\r\n# Keyspace\r\n' How can I turn it to an object? like: { redis_version:2.6.16, redis_git_sha1:00000000, redis_git_dirty:0, ...... } so that I can read each property's value, get information I need

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  • C# Random Number Generator getting stuck in a cycle

    - by Jean Azzopardi
    Hi, I am using .NET to create an artificial life program and I am using C#'s pseudo random class defined in a Singleton. The idea is that if I use the same random number generator throughout the application, I could merely save the seed and then reload from the seed to recompute a certain interesting run. public sealed class RandomNumberGenerator : Random { private static readonly RandomNumberGenerator instance = new RandomNumberGenerator(); RandomNumberGenerator() { } public static RandomNumberGenerator Instance { get { return instance; } } } I also wanted a method that could give me two different random numbers. public static Tuple<int, int> TwoDifferentRandomNumbers(this Random rnd, int minValue, int maxValue) { if (minValue >= maxValue) throw new ArgumentOutOfRangeException("maxValue", "maxValue must be greater than minValue"); if (minValue + 1 == maxValue) return Tuple.Create<int, int>(minValue, maxValue); int rnd1 = rnd.Next(minValue, maxValue); int rnd2 = rnd.Next(minValue, maxValue); while (rnd1 == rnd2) { rnd2 = rnd.Next(minValue, maxValue); } return Tuple.Create<int, int>(rnd1, rnd2); } The problem is that sometimes rnd.Next(minValue,maxValuealways returns minValue. If I breakpoint at this point and try creating a double and setting it to rnd.NextDouble(), it returns 0.0. Anyone know why this is happening? I know that it is a pseudo random number generator, but frankly, I hadn't expected it to lock at 0. The random number generator is being accessed from multiple threads... could this be the source of the problem?

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  • How can I make an even more random number in ActionScript 2.0

    - by Theo
    I write a piece of software that runs inside banner ads which generates millions of session IDs every day. For a long time I've known that the random number generator in Flash is't random enough to generate sufficiently unique IDs, so I've employed a number of tricks to get even more random numbers. However, in ActionScript 2.0 it's not easy, and I'm seeing more and more collisions, so I wonder if there is something I've overlooked. As far as I can tell the problem with Math.random() is that it's seeded by the system time, and when you have sufficient numbers of simultaneous attempts you're bound to see collisions. In ActionScript 3.0 I use the System.totalMemory, but there's no equivalent in ActionScript 2.0. AS3 also has Font.enumerateFonts, and a few other things that are different from system to system. On the server side I also add the IP address to the session ID, but even that isn't enough (for example, many large companies use a single proxy server and that means that thousands of people all have the same IP -- and since they tend to look at the same sites, with the same ads, roughly at the same time, there are many session ID collisions). What I need isn't something perfectly random, just something that is random enough to dilute the randomness I get from Math.random(). Think of it this way: there is a certain chance that two people will generate the same random number sequence using only Math.random(), but the chance of two people generating the same sequence and having, say, the exact same list of fonts is significantly lower. I cannot rely on having sufficient script access to use ExternalInterface to get hold of things like the user agent, or the URL of the page. I don't need suggestions of how to do it in AS3, or any other system, only AS2 -- using only what's available in the standard APIs. The best I've come up with so far is to use the list of microphones (Microphone.names), but I've also tried to make some fingerprinting using some of the properties in System.capabilities, I'm not sure how much randomness I can get out of that though so I'm not using that at the moment. I hope I've overlooked something.

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  • Oracle Date Format Convert Hour-Minute to Interval and Disregard Year-Month-Day

    - by dlite922
    I need to compare an event's half-way midpoint between a start and stop time of day. Right now i'm converting the dates you see on the right, to HH:MM and the comparison works until midnight. the query says: WHERE half BETWEEN pStart and pStop. As you can see below, pStart and pStap have January 1st 2000 dates, this is because the year month day are not important to me... Valid Data: +-------+--------+-------+---------------------+---------------------+---------------------+ | half | pStart | pStop | half2 | pStart2 | pStop2 | +-------+--------+-------+---------------------+---------------------+---------------------+ | 19:00 | 19:00 | 23:00 | 2012-11-04 19:00:00 | 2000-01-01 19:00:00 | 2000-01-01 23:00:00 | | 20:00 | 19:00 | 23:00 | 2012-11-04 20:00:00 | 2000-01-01 19:00:00 | 2000-01-01 23:00:00 | | 21:00 | 19:00 | 23:00 | 2012-11-04 21:00:00 | 2000-01-01 19:00:00 | 2000-01-01 23:00:00 | | 23:00 | 20:00 | 23:00 | 2012-11-05 23:00:00 | 2000-01-01 20:00:00 | 2000-01-01 23:00:00 | +-------+--------+-------+---------------------+---------------------+---------------------+ Now observe what happens when pStop is midnight or later... Valid Data that breaks it: +-------+--------+-------+---------------------+---------------------+---------------------+ | half | pStart | pStop | half2 | pStart2 | pStop2 | +-------+--------+-------+---------------------+---------------------+---------------------+ | 23:00 | 22:00 | 00:00 | 2012-11-04 23:00:00 | 2000-01-01 22:00:00 | 2000-01-01 00:00:00 | | 23:30 | 23:00 | 02:00 | 2012-11-05 23:30:00 | 2000-01-01 23:00:00 | 2000-01-01 02:00:00 | +-------+--------+-------+---------------------+---------------------+---------------------+ Thus my where clause translates to: WHERE 19:00 BETWEEN 22:00 AND 00:00 ...which returns false and I miss those two correct rows above. Question: Is there a way to show those dates as integer interval so that saying half BETWEEN pStart and pStop are correct? I thought about adding 24 when pStop is less than pStart to make 00:00 into 24:00 but don't know an easy way to do that without long string concatenations and number conversions. This would solve the problem because pStart pStop difference will never be longer than 6 hours. Note: (The Query is much more complex. It has other irrelevant date calculations, but the result are show above. DATE_FORMAT(%H:%i) is applied to the first three columns and no formatting to the last three) Thanks for your help:

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  • Algorithm to calculate the number of divisors of a given number

    - by sker
    What would be the most optimal algorithm (performance-wise) to calculate the number of divisors of a given number? It'll be great if you could provide pseudocode or a link to some example. EDIT: All the answers have been very helpful, thank you. I'm implementing the Sieve of Atkin and then I'm going to use something similar to what Jonathan Leffler indicated. The link posted by Justin Bozonier has further information on what I wanted.

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  • number several equations with only one number

    - by Tim
    Hi, How can I number several equations in a align environment using only one number? For example \begin{align} w^T x_i + b \geqslant 1-\xi_i \text{ if } y_i=1, \nonumber \\ w^T x_i + b \leqslant -1+\xi_i \text{ if } y_i=-1, \end{align} The numbering will appear next to the second equation. But it would be better if it appears between the lines of the two equations. In this case how to label this group of equations for later referring to? Thanks and regards!

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  • Warning: PDOStatement::execute(): SQLSTATE[HY093]: Invalid parameter number: number of bound variabl

    - by Thomas
    Hi, I'm working with PHP PDO and I have the following problem: Warning: PDOStatement::execute(): SQLSTATE[HY093]: Invalid parameter number: number of bound variables does not match number of tokens in /var/www/site/classes/enterprise.php on line 63 Here is my code: public function getCompaniesByCity(City $city, $options = null) { $database = Connection::getConnection(); if(empty($options)) { $statement = $database-prepare("SELECT * FROM empresas WHERE empresas.cidades_codigo = ?"); $statement-bindValue(1, $city-getId()); } else { $sql = "SELECT * FROM empresas INNER JOIN prods_empresas ON prods_empresas.empresas_codigo = empresas.codigo WHERE "; foreach($options as $option) { $sql .= 'prods_empresas.produtos_codigo = ? OR '; } $sql = substr($sql, 0, -4); $sql .= ' AND empresas.cidades_codigo = ?'; $statement = $database-prepare($sql); echo $sql; foreach($options as $i = $option) { $statement-bindValue($i + 1, $option-getId()); } $statement-bindValue(count($options), $city-getId()); } $statement-execute(); $objects = $statement-fetchAll(PDO::FETCH_OBJ); $companies = array(); if(!empty($objects)) { foreach($objects as $object) { $data = array( 'id' = $object-codigo, 'name' = $object-nome, 'link' = $object-link, 'email' = $object-email, 'details' = $object-detalhes, 'logo' = $object-logo ); $enterprise = new Enterprise($data); array_push($companies, $enterprise); } return $companies; } } Thank you very much!

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  • How to get element order number

    - by martin-masiar
    Hello everyone, how can i get order number of some element by javascript/jquery? <ul> <li>Anton</li> <li class="abc">Victor</li> <li class="abc">Simon</li> <li>Adam</li> <li>Peter</li> <li class="abc">Tom</li> </ul> There is 3xli with abc class. Now I need to get order(sequence) number of Simon li. Thanks in advance

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  • T-SQL - Left Outer Joins - Filters in the where clause versus the on clause.

    - by Greg Potter
    I am trying to compare two tables to find rows in each table that is not in the other. Table 1 has a groupby column to create 2 sets of data within table one. groupby number ----------- ----------- 1 1 1 2 2 1 2 2 2 4 Table 2 has only one column. number ----------- 1 3 4 So Table 1 has the values 1,2,4 in group 2 and Table 2 has the values 1,3,4. I expect the following result when joining for Group 2: `Table 1 LEFT OUTER Join Table 2` T1_Groupby T1_Number T2_Number ----------- ----------- ----------- 2 2 NULL `Table 2 LEFT OUTER Join Table 1` T1_Groupby T1_Number T2_Number ----------- ----------- ----------- NULL NULL 3 The only way I can get this to work is if I put a where clause for the first join: PRINT 'Table 1 LEFT OUTER Join Table 2, with WHERE clause' select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table1 LEFT OUTER join table2 --****************************** on table1.number = table2.number --****************************** WHERE table1.groupby = 2 AND table2.number IS NULL and a filter in the ON for the second: PRINT 'Table 2 LEFT OUTER Join Table 1, with ON clause' select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table2 LEFT OUTER join table1 --****************************** on table2.number = table1.number AND table1.groupby = 2 --****************************** WHERE table1.number IS NULL Can anyone come up with a way of not using the filter in the on clause but in the where clause? The context of this is I have a staging area in a database and I want to identify new records and records that have been deleted. The groupby field is the equivalent of a batchid for an extract and I am comparing the latest extract in a temp table to a the batch from yesterday stored in a partioneds table, which also has all the previously extracted batches as well. Code to create table 1 and 2: create table table1 (number int, groupby int) create table table2 (number int) insert into table1 (number, groupby) values (1, 1) insert into table1 (number, groupby) values (2, 1) insert into table1 (number, groupby) values (1, 2) insert into table2 (number) values (1) insert into table1 (number, groupby) values (2, 2) insert into table2 (number) values (3) insert into table1 (number, groupby) values (4, 2) insert into table2 (number) values (4) EDIT: A bit more context - depending on where I put the filter I different results. As stated above the where clause gives me the correct result in one state and the ON in the other. I am looking for a consistent way of doing this. Where - select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table1 LEFT OUTER join table2 --****************************** on table1.number = table2.number --****************************** WHERE table1.groupby = 2 AND table2.number IS NULL Result: T1_Groupby T1_Number T2_Number ----------- ----------- ----------- 2 2 NULL On - select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table1 LEFT OUTER join table2 --****************************** on table1.number = table2.number AND table1.groupby = 2 --****************************** WHERE table2.number IS NULL Result: T1_Groupby T1_Number T2_Number ----------- ----------- ----------- 1 1 NULL 2 2 NULL 1 2 NULL Where (table 2 this time) - select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table2 LEFT OUTER join table1 --****************************** on table2.number = table1.number AND table1.groupby = 2 --****************************** WHERE table1.number IS NULL Result: T1_Groupby T1_Number T2_Number ----------- ----------- ----------- NULL NULL 3 On - select table1.groupby as [T1_Groupby], table1.number as [T1_Number], table2.number as [T2_Number] from table2 LEFT OUTER join table1 --****************************** on table2.number = table1.number --****************************** WHERE table1.number IS NULL AND table1.groupby = 2 Result: T1_Groupby T1_Number T2_Number ----------- ----------- ----------- (0) rows returned

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  • PHP - Math - Round Number Function

    - by aSeptik
    Hi All guys! this time i have a math question for you! Assuming we have three numbers one is the Number of Votes the second is the Total Values and the last is the Units Ratings. units_ratings can be a number from 1 to 10; if ( total_values / units_ratings != number_of_votes ) { //do something for let the "number_of_votes" fit the division! } I ask this to you, cause i want know the best (fastest) way of achieve this! Thanks!

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  • Noob Droid Question regarding random number

    - by Pete Herbert Penito
    Brand new to droid programming, but would love to learn as much as possible, so I finally got my emulator working correctly, I even got a hello world button to work, I'm attempting to make this button display a random number, I've googled this and came up with this code: Random generator = new Random(); int n = generator.nextInt(n); I fixed the Random function by including some Random java utility. I'm assuming this code above goes in the .java file of the project, so my button code looks as follows (tested and works): PopUpText.makeText(v.getContext(), "Hello World", PopUpText.LENGTH_LONG).show(); I figured I could replace "Hello World" with n to display the number in the box, however the following error is stopping the compile: The local variable n may not have been initialized Any ideas why this is happening? Any advice would be hugely appreciated.

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  • Fastest method to define whether a number is a triangular number

    - by psihodelia
    A triangular number is the sum of the n natural numbers from 1 to n. What is the fastest method to find whether a given positive integer number is a triangular one? I suppose, there must be a hidden pattern in a binary representation of such numbers (like if you need to find whether a number is even/odd you check its least significant bit). Here is a cut of the first 1200th up to 1300th triangular numbers, you can easily see a bit-pattern here (if not, try to zoom out): (720600, '10101111111011011000') (721801, '10110000001110001001') (723003, '10110000100000111011') (724206, '10110000110011101110') (725410, '10110001000110100010') (726615, '10110001011001010111') (727821, '10110001101100001101') (729028, '10110001111111000100') (730236, '10110010010001111100') (731445, '10110010100100110101') (732655, '10110010110111101111') (733866, '10110011001010101010') (735078, '10110011011101100110') (736291, '10110011110000100011') (737505, '10110100000011100001') (738720, '10110100010110100000') (739936, '10110100101001100000') (741153, '10110100111100100001') (742371, '10110101001111100011') (743590, '10110101100010100110') (744810, '10110101110101101010') (746031, '10110110001000101111') (747253, '10110110011011110101') (748476, '10110110101110111100') (749700, '10110111000010000100') (750925, '10110111010101001101') (752151, '10110111101000010111') (753378, '10110111111011100010') (754606, '10111000001110101110') (755835, '10111000100001111011') (757065, '10111000110101001001') (758296, '10111001001000011000') (759528, '10111001011011101000') (760761, '10111001101110111001') (761995, '10111010000010001011') (763230, '10111010010101011110') (764466, '10111010101000110010') (765703, '10111010111100000111') (766941, '10111011001111011101') (768180, '10111011100010110100') (769420, '10111011110110001100') (770661, '10111100001001100101') (771903, '10111100011100111111') (773146, '10111100110000011010') (774390, '10111101000011110110') (775635, '10111101010111010011') (776881, '10111101101010110001') (778128, '10111101111110010000') (779376, '10111110010001110000') (780625, '10111110100101010001') (781875, '10111110111000110011') (783126, '10111111001100010110') (784378, '10111111011111111010') (785631, '10111111110011011111') (786885, '11000000000111000101') (788140, '11000000011010101100') (789396, '11000000101110010100') (790653, '11000001000001111101') (791911, '11000001010101100111') (793170, '11000001101001010010') (794430, '11000001111100111110') (795691, '11000010010000101011') (796953, '11000010100100011001') (798216, '11000010111000001000') (799480, '11000011001011111000') (800745, '11000011011111101001') (802011, '11000011110011011011') (803278, '11000100000111001110') (804546, '11000100011011000010') (805815, '11000100101110110111') (807085, '11000101000010101101') (808356, '11000101010110100100') (809628, '11000101101010011100') (810901, '11000101111110010101') (812175, '11000110010010001111') (813450, '11000110100110001010') (814726, '11000110111010000110') (816003, '11000111001110000011') (817281, '11000111100010000001') (818560, '11000111110110000000') (819840, '11001000001010000000') (821121, '11001000011110000001') (822403, '11001000110010000011') (823686, '11001001000110000110') (824970, '11001001011010001010') (826255, '11001001101110001111') (827541, '11001010000010010101') (828828, '11001010010110011100') (830116, '11001010101010100100') (831405, '11001010111110101101') (832695, '11001011010010110111') (833986, '11001011100111000010') (835278, '11001011111011001110') (836571, '11001100001111011011') (837865, '11001100100011101001') (839160, '11001100110111111000') (840456, '11001101001100001000') (841753, '11001101100000011001') (843051, '11001101110100101011') (844350, '11001110001000111110') For example, can you also see a rotated normal distribution curve, represented by zeros between 807085 and 831405?

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  • Calculate the number of ways to roll a certain number

    - by helloworld
    I'm a high school Computer Science student, and today I was given a problem to: Program Description: There is a belief among dice players that in throwing three dice a ten is easier to get than a nine. Can you write a program that proves or disproves this belief? Have the computer compute all the possible ways three dice can be thrown: 1 + 1 + 1, 1 + 1 + 2, 1 + 1 + 3, etc. Add up each of these possibilities and see how many give nine as the result and how many give ten. If more give ten, then the belief is proven. I quickly worked out a brute force solution, as such int sum,tens,nines; tens=nines=0; for(int i=1;i<=6;i++){ for(int j=1;j<=6;j++){ for(int k=1;k<=6;k++){ sum=i+j+k; //Ternary operators are fun! tens+=((sum==10)?1:0); nines+=((sum==9)?1:0); } } } System.out.println("There are "+tens+" ways to roll a 10"); System.out.println("There are "+nines+" ways to roll a 9"); Which works just fine, and a brute force solution is what the teacher wanted us to do. However, it doesn't scale, and I am trying to find a way to make an algorithm that can calculate the number of ways to roll n dice to get a specific number. Therefore, I started generating the number of ways to get each sum with n dice. With 1 die, there is obviously 1 solution for each. I then calculated, through brute force, the combinations with 2 and 3 dice. These are for two: There are 1 ways to roll a 2 There are 2 ways to roll a 3 There are 3 ways to roll a 4 There are 4 ways to roll a 5 There are 5 ways to roll a 6 There are 6 ways to roll a 7 There are 5 ways to roll a 8 There are 4 ways to roll a 9 There are 3 ways to roll a 10 There are 2 ways to roll a 11 There are 1 ways to roll a 12 Which looks straightforward enough; it can be calculated with a simple linear absolute value function. But then things start getting trickier. With 3: There are 1 ways to roll a 3 There are 3 ways to roll a 4 There are 6 ways to roll a 5 There are 10 ways to roll a 6 There are 15 ways to roll a 7 There are 21 ways to roll a 8 There are 25 ways to roll a 9 There are 27 ways to roll a 10 There are 27 ways to roll a 11 There are 25 ways to roll a 12 There are 21 ways to roll a 13 There are 15 ways to roll a 14 There are 10 ways to roll a 15 There are 6 ways to roll a 16 There are 3 ways to roll a 17 There are 1 ways to roll a 18 So I look at that, and I think: Cool, Triangular numbers! However, then I notice those pesky 25s and 27s. So it's obviously not triangular numbers, but still some polynomial expansion, since it's symmetric. So I take to Google, and I come across this page that goes into some detail about how to do this with math. It is fairly easy(albeit long) to find this using repeated derivatives or expansion, but it would be much harder to program that for me. I didn't quite understand the second and third answers, since I have never encountered that notation or those concepts in my math studies before. Could someone please explain how I could write a program to do this, or explain the solutions given on that page, for my own understanding of combinatorics? EDIT: I'm looking for a mathematical way to solve this, that gives an exact theoretical number, not by simulating dice

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