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Language: Crazy Thairs
Description These days, Sempr is crazed on one problem named Crazy Thair. Given N (1 ≤ N ≤ 50000) numbers, which are no more than 109, Crazy Thair is a group of 5 numbers {i, j, k, l, m} satisfying: 1. 1 ≤ i < j < k < l < m ≤ N For example, in the sequence {2, 1, 3, 4, 5, 7, 6},there are four Crazy Thair groups: {1, 3, 4, 5, 6}, {2, 3, 4, 5, 6}, {1, 3, 4, 5, 7} and {2, 3, 4, 5, 7}. Could you help Sempr to count how many Crazy Thairs in the sequence? Input Input contains several test cases. Each test case begins with a line containing a number N, followed by a line containing N numbers. Output Output the amount of Crazy Thairs in each sequence. Sample Input 5 1 2 3 4 5 7 2 1 3 4 5 7 6 7 1 2 3 4 5 6 7 Sample Output 1 4 21 Source POJ Monthly--2007.09.09, tdzl2003 |
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