Implementing Shell Sort Algorithm with Java

Shell Sort is an improved version of Insertion Sort that reduces the number of element movements during inversions by grouping elements. The core idea is to introduce a step size (Gap), which divides the array into Gap subsequences. After performing insertion sort on each subsequence, the Gap is gradually reduced to 1 (equivalent to standard Insertion Sort). Algorithm steps: Initialize Gap as half the array length. Perform insertion sort on each subsequence, then reduce the Gap and repeat until Gap becomes 0. In Java implementation, the outer loop controls the Gap to decrease from n/2. The inner loop iterates through elements, using a temporary variable to store the current element, then compares and shifts elements forward to their correct positions to complete insertion. Testing with the array {12, 34, 54, 2, 3} results in the sorted output [2, 3, 12, 34, 54]. By gradually ordering elements through grouping, Shell Sort improves efficiency, and optimizing the step size sequence (e.g., 3k+1) can further enhance performance.