|
I I U C O N L I N E C O N T E S T 2 0 0 8 |
|
|
Problem B: Triples |
|
|
Input: standard input |
|
|
|
|
|
Given a sequence of positive integers. You need to find the number of triples in that sequence. For this problem, (x, y, z) constructs a triple if and only if x + y = z. So, (1, 2, 3) is a triple, where (3, 4, 5) is not.
|
|
|
Input |
|
|
Each input set starts with a positive integer N. Next few lines contain N positive integers. Input is terminated by EOF.
|
|
|
Output |
|
|
For each case, print the number of triples in a line.
|
|
|
Constraints |
|
|
- 3 ≤ N ≤ 5000
|
|
|
Sample Input |
Output for Sample Input |
|
6 1 2 3 4 5 6 6 1 2 4 8 16 32 3 100000000 200000000 100000000 5 1 1 1 2 2 |
6 0 1 6 |
|
|
|
|
Problem setter: Md. Kamruzzaman |
|