The problem can be reproduced using VS 2013 Express. It crashed when internal vector implementation tried to deallocate the original vector.

However, the problem can solved by using 'new' instead of 'malloc'.

Anyone can shed some light on this?

struct UndirectedGraphNode {
   int label;
   vector<UndirectedGraphNode *> neighbors;
   UndirectedGraphNode(int x) : label(x) {};
};

int main(int argc, char** argv)
{
    UndirectedGraphNode* node1 = (UndirectedGraphNode*)malloc(sizeof(UndirectedGraphNode));
    node1->label = 0;
    node1->neighbors.resize(2); 
    return 0;
}