ArithmeticTriplets-LCQ.cpp

/*
Number of Arithmetic Triplets

You are given a 0-indexed, strictly increasing integer array nums and a positive integer diff. A triplet (i, j, k) is an arithmetic triplet if the following conditions are met:

i < j < k,
nums[j] - nums[i] == diff, and
nums[k] - nums[j] == diff.
Return the number of unique arithmetic triplets.

 

Example 1:

Input: nums = [0,1,4,6,7,10], diff = 3
Output: 2
Explanation:
(1, 2, 4) is an arithmetic triplet because both 7 - 4 == 3 and 4 - 1 == 3.
(2, 4, 5) is an arithmetic triplet because both 10 - 7 == 3 and 7 - 4 == 3. 

Example 2:

Input: nums = [4,5,6,7,8,9], diff = 2
Output: 2
Explanation:
(0, 2, 4) is an arithmetic triplet because both 8 - 6 == 2 and 6 - 4 == 2.
(1, 3, 5) is an arithmetic triplet because both 9 - 7 == 2 and 7 - 5 == 2.
 

Constraints:

3 <= nums.length <= 200
0 <= nums[i] <= 200
1 <= diff <= 50
nums is strictly increasing.
*/

class Solution {
public:
    int arithmeticTriplets(vector<int>& nums, int diff) {
        int cnt=0;
        for(int i=0;i<nums.size();i++){
            for(int j=i+1;j<nums.size();j++){
                for(int k=j+1;k<nums.size();k++){
                    if(nums[j]-nums[i]==diff && nums[k]-nums[j]==diff)
                        cnt++;
                }
            }
        }
        return cnt;
    }
};