How to implement a quick search algorithm in the C language?

A common way to implement a fast searching algorithm in the C language is to combine the quicksort algorithm with binary search.

The QuickSort algorithm is used to sort an array according to a specific rule for the purpose of searching. The specific steps are as follows:

1. Choose a reference element, which can be any element in the array.
2. Divide the array into two parts such that the elements on the left are less than or equal to the pivot element, and the elements on the right are greater than or equal to the pivot element.
3. Perform quicksort recursively on the left and right partitions.
4. Merge the left and right parts to get the final sorted result.

After the quicksort is completed, we can use binary search to quickly locate the position of the element to be found in the sorted array. The specific steps of binary search are as follows:

1. Establish the left and right boundaries of the array, initially with the left boundary at 0 and the right boundary at the length of the array minus one.
2. Calculate the index value of the middle position as mid = (left + right) / 2.
3. If the element being searched for is equal to the element at the middle position, then return the index of the middle position.
4. If the element to be searched for is less than the middle element, then update the right boundary to be mid – 1.
5. If the element to be searched for is greater than the element at the middle position, then update the left boundary as mid + 1.
6. If the element being searched for is still not found when the loop ends, return a flag indicating search failure.

By combining the quicksort algorithm with binary search, quick searching of large-scale data can be achieved in a shorter time.