Count Triplets With Given Sum In Sorted Array

The task is to count triplets in a sorted array whose sum is equal to a given target. The approach uses the two-pointer technique, where the first element of the triplet is fixed, and two pointers are used to explore possible pairs. The algorithm iterates through each element and adjusts the left and right pointers based on the sum of the current triplet, either incrementing the left pointer or decrementing the right pointer to match the target. If a valid triplet is found, the frequencies of the current elements at the left and right pointers are counted to avoid duplicates and update the result accordingly.

The provided C++ code demonstrates this approach, efficiently counting the number of valid triplets. It uses the two-pointer technique to traverse the array and finds triplets where the sum of the elements equals the target. The time complexity of this approach is O(n^2), as for each index, two pointers traverse the array. This method also handles duplicates by counting the frequency of elements at the left and right pointers. The program then returns the total number of triplets with a sum equal to the target.

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