This is a Binary-Search Tree template written by Leon.

This problem can be solved by at least 4 methods:

• Quick Sort
• Binary Search Tree
• Trie and Depth First Search
• Map

Here is my pseudo code:

1
2
3
4
5
6
7

count <-- 0
for each edge( two points) do
    find the possible other two points to construct a square, there will be two pairs.
    for each pair of points do
        use binary search or hash to check if both points are given
        if both are given then count <-- count+1
return count

When VC6.0 breaks down due to a stack overflow, sometimes you can adjust the stack allocations to get around this problem.

Project->Settings->Link->Category->Output

Write the bytes you need in Stack allocations->Reserve.