Leetcode 1395. Count Number of Teams

There are n soldiers standing in a line. Each soldier is assigned a unique rating value.

You have to form a team of 3 soldiers amongst them under the following rules:

• Choose 3 soldiers with index (i, j, k) with rating (rating[i], rating[j], rating[k]).

• A team is valid if: (rating[i] < rating[j] < rating[k]) or (rating[i] > rating[j] > rating[k]) where (0 <= i < j < k < n).

Return the number of teams you can form given the conditions. (soldiers can be part of multiple teams).

Example 1:

Input: rating = [2,5,3,4,1]Output: 3Explanation: We can form three teams given the conditions. (2,3,4), (5,4,1), (5,3,1).

Example 2:

Input: rating = [2,1,3]Output: 0Explanation: We can't form any team given the conditions.

Example 3:

Input: rating = [1,2,3,4]Output: 4

Constraints:

• n == rating.length

• 3 <= n <= 1000

• 1 <= rating[i] <= 105

• All the integers in rating are unique.

遍历所有位置，计算出来4个参数的值，然后4个参数的乘积和就是了。

居然没想到，，，，汗颜。

Runtime43 ms

Beats

38.35%

Memory42.6 MB

Beats

54.39%

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