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Leetcode 2475: Number of Unequal Triplets in Array Solution

Here, we will see how to solve Number of Unequal Triplets in Array Solution of leet code 2475 problem.

You are given a 0-indexed array of positive integers nums. Find the number of triplets (i, j, k) that meet the following conditions:

  • 0 <= i < j < k < nums.length
  • nums[i]nums[j], and nums[k] are pairwise distinct.
    • In other words, nums[i] != nums[j]nums[i] != nums[k], and nums[j] != nums[k].

You have to return the number of triplets that meet the conditions.

Example 1:

Input: nums = [5,5,3,5,4]
Output: 3
Explanation: The following triplets meet the conditions:
- (0, 2, 4) because 5 != 3 != 4
- (1, 2, 4) because 5 != 3 != 4
- (2, 3, 4) because 3 != 5 != 4
Since there are 3 triplets, we return 3.
Note that (2, 0, 4) is not a valid triplet because 2 > 0.

Example 2:

Input: nums = [2,2,2,2,2]
Output: 0
Explanation: No triplets meet the conditions so we return 0.

Number of Unequal Triplets in Array Solution code in C++ and Go lang:

Here, we will be solving problem in multiple ways with code.

C++ code 1:

class Solution {
public:
    int unequalTriplets(vector<int>& nums) {
        int n = nums.size();
        int ret = n * (n - 1) * (n - 2) / 6;
        map<int, int> count;
        for (int i: nums) {
            count[i] += 1;
        }
        for (auto p: count) {
            int f = p.second;
            ret -= f * (f - 1) * (n - f) / 2;
            ret -= f * (f - 1) * (f - 2) / 6;
        }
        return ret;
    }
};

C++ code 2:

class Solution {
public:
    int unequalTriplets(vector<int>& nums) {
        int n = nums.size();
        int ret = 0;
        for (int i = 0; i < n; ++i) {
            for (int j = i + 1; j < n; ++j) {
                if (nums[i] == nums[j]) {
                    continue;
                }
                for (int k = j + 1; k < n; ++k) {
                    if (nums[k] == nums[j] || nums[k] == nums[i]) {
                        continue;
                    }
                    ++ret;
                }
            }
        }
        return ret;
    }
};

C++ code 3:

class Solution {
public:
    int unequalTriplets(vector<int>& nums) {
        int count = 0;
        
        for(int i = 0; i < nums.size() - 2; i++) {
            for(int j = i + 1; j < nums.size() - 1; j++) {
                for(int k = j + 1; k < nums.size(); k++) {
                    if ((nums[i] != nums[j]) && (nums[i] != nums[k]) && (nums[j] != nums[k])) {
                        count++;
                    }
                } 
            }
        }
        return count;
    }
};

Go code 1:

func unequalTriplets(nums []int) int {
    var i, j, k, count = 0, 0, 0, 0
    
    for ; i < len(nums) - 2; i++ {
        for j = i + 1; j < len(nums) - 1; j++ {
            for k = j + 1; k < len(nums); k++ {
                if (nums[i] != nums[j]) && (nums[i] != nums[k]) && (nums[j] != nums[k]) {
                    count++;
                }
            }
        }
    }
    return count
}

Output:

Input: nums = [5,5,3,5,4]
Output: 3

To check more leetcode problem’s solution. Pls click given below link:

https://www.techieindoor.com/category/leetcode/

https://www.techieindoor.com/category/leetcode/

Posted in C++, Easy, golang, golang program, Leetcode

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