Need to devise a number crunching algorithm
- by Ravi Gupta
I stumbled upon this question:
7 power 7 is 823543. Which higher power of 7 ends with 823543 ?
How should I go about it ? The one I came up with is very slow, it keeps on multiplying by 7 and checks last 6 digits of the result for a match.
I tried with Lou's code:
int x=1;
for (int i=3;i<=100000000;i=i+4){
x=(x*7)%1000000;
System.out.println("i="+ i+" x= "+x);
if (x==823543){
System.out.println("Ans "+i);}
}
And CPU sounds like a pressure cooker but couldn't get the answer :(
