A11020 | Makes And The Product
时间限制1s
内存限制256MB
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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 $a_{i}·a_{j}·a_{k}$ 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 $n (3<=n<=10^{5})$ — the number of elements in array $a$ . The second line contains $n$ positive integer numbers $a_{i} (1<=a_{i}<=10^{9})$ — 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 $a_{i}·a_{j}·a_{k}$ 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
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.
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.
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评测结果：Accepted