_1395.java

package com.fishercoder.solutions;

/**
 * 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: 3
 * Explanation: 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: 0
 * Explanation: We can't form any team given the conditions.
 *
 * Example 3:
 * Input: rating = [1,2,3,4]
 * Output: 4
 *
 * Constraints:
 * n == rating.length
 * 1 <= n <= 200
 * 1 <= rating[i] <= 10^5
 * */
public class _1395 {
    public static class Solution1 {
        public int numTeams(int[] rating) {
            int count = 0;
            //check increasing
            for (int i = 0; i < rating.length - 2; i++) {
                for (int j = i + 1; j < rating.length - 1; j++) {
                    if (rating[j] > rating[i]) {
                        for (int k = j + 1; k < rating.length; k++) {
                            if (rating[k] > rating[j]) {
                                count++;
                            }
                        }
                    }
                }
            }

            //check decreasing
            for (int i = 0; i < rating.length - 2; i++) {
                for (int j = i + 1; j < rating.length - 1; j++) {
                    if (rating[j] < rating[i]) {
                        for (int k = j + 1; k < rating.length; k++) {
                            if (rating[k] < rating[j]) {
                                count++;
                            }
                        }
                    }
                }
            }
            return count;
        }
    }
}