Today I have done leetcode's April LeetCoding Challenge with cpp.

April LeetCoding Challenge 14

Description

Count Good Triplets

Given an array of integers arr, and three integers a, b and c. You need to find the number of good triplets.

A triplet (arr[i], arr[j], arr[k]) is good if the following conditions are true:

• 0 <= i < j < k < arr.length
• |arr[i] - arr[j]| <= a
• |arr[j] - arr[k]| <= b
• |arr[i] - arr[k]| <= c

Where |x| denotes the absolute value of x.

Return the number of good triplets.

Example 1:

Input: arr = [3,0,1,1,9,7], a = 7, b = 2, c = 3
Output: 4
Explanation: There are 4 good triplets: [(3,0,1), (3,0,1), (3,1,1), (0,1,1)].

Example 2:

Input: arr = [1,1,2,2,3], a = 0, b = 0, c = 1
Output: 0
Explanation: No triplet satisfies all conditions.

Constraints:

• 3 <= arr.length <= 100
• 0 <= arr[i] <= 1000
• 0 <= a, b, c <= 1000

Solution

class Solution {
public:
  int countGoodTriplets(vector<int>& arr, int a, int b, int c) {
    int len = arr.size();
    int answer = 0;
    for(int i = 0; i < len - 2; ++i) {
      for(int j = i + 1; j < len - 1; ++j) {
        for(int k = j + 1; k < len; ++k) {
          answer += (abs(arr[i] - arr[j]) <= a && abs(arr[j] - arr[k]) <= b && abs(arr[i] - arr[k]) <= c);
        }
      }
    }
    return answer;
  }
};

// Accepted
// 92/92 cases passed (8 ms)
// Your runtime beats 51.06 % of cpp submissions
// Your memory usage beats 43.88 % of cpp submissions (11.1 MB)