Interview Questions/Coding/Weakness Triplet Counter

Weakness Triplet Counter

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Hard

Weakness Triplet Counter

A ranking review receives a sequence of strength scores. A weakness pattern is a triple of positions i < j < k where the scores strictly decrease from left to right. For each sequence, count the number of such triples. Input Format: The first line contains t. Each case contains n followed by n strength scores. Output Format: For each case, print the number of decreasing triples.

Examples

Example 1
Input:
2
5
5 3 4 2 1
4
1 2 3 4
Output:
7

Explanation: The first sequence has several decreasing triples; the increasing sequence has none.

Approach hint

Think of each position as the middle of the triple.

Common mistake

Skipping assumptions, edge cases, or trade-offs can make an otherwise good answer feel incomplete.

solution.cpp