CF817B.Makes And The Product
普及/提高-
通过率:0%
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题目描述
After returning from the army Makes received a gift — an array a consisting of n positive integer numbers. He hadn't been solving problems for a long time, so he became interested to answer a particular question: how many triples of indices (i, j, k) ( i<j<k ), such that ai⋅aj⋅ak is minimum possible, are there in the array? Help him with it!
输入格式
The first line of input contains a positive integer number n (3<=n<=105) — the number of elements in array a . The second line contains n positive integer numbers ai (1<=ai<=109) — the elements of a given array.
输出格式
Print one number — the quantity of triples (i, j, k) such that i, j and k are pairwise distinct and ai⋅aj⋅ak is minimum possible.
输入输出样例
输入#1
4 1 1 1 1
输出#1
4
输入#2
5 1 3 2 3 4
输出#2
2
输入#3
6 1 3 3 1 3 2
输出#3
1
说明/提示
In the first example Makes always chooses three ones out of four, and the number of ways to choose them is 4 .
In the second example a triple of numbers (1,2,3) is chosen (numbers, not indices). Since there are two ways to choose an element 3 , then the answer is 2 .
In the third example a triple of numbers (1,1,2) is chosen, and there's only one way to choose indices.