Existence of a Substring in a String and Its Reverse - Solution & Explanation

This approach involves sorting the array first, then using a two-pointer technique to solve the problem. By sorting, we can utilize the sorted order to efficiently find pairs or triplets that meet our requirements.

This C code uses the qsort function to sort the array. A pointer approach is then used to find a pair that sums to the target. It iterates from both ends towards the center.

In this approach, a hash map (or dictionary) is used to keep track of the elements we have seen so far and their respective indices. This allows for efficient look-up to find pairs that sum to the target value without needing to sort the array.

This C code creates a basic hash table using an array of pointers to store key-value pairs. The target complement is computed for each element, and we check if it has been previously added, ensuring a quick lookup.