Create ShellSortAditya.java

Shell Sort is an optimized version of Insertion Sort that allows the exchange of far-apart elements.

The array is sorted using gaps that reduce by half each iteration.

When the gap becomes 1, it effectively becomes a normal insertion sort — but the array is mostly sorted by then.

Complexity:
Best case: O(n log n)

Average case: O(n^(3/2))

Worst case: O(n²)

Space complexity: O(1)

Author: aditya-chouksey

Java/algorithms/sorting/ShellSortAditya.java

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+#include <iostream>
+#include <vector>
+using namespace std;
+
+// Function to perform Shell Sort
+void shellSort(vector<int> &arr) {
+    int n = arr.size();
+
+    // Start with a large gap, then reduce the gap
+    for (int gap = n / 2; gap > 0; gap /= 2) {
+        // Do a gapped insertion sort for this gap size
+        for (int i = gap; i < n; i++) {
+            int temp = arr[i];
+            int j;
+            // Shift earlier gap-sorted elements until the correct location is found
+            for (j = i; j >= gap && arr[j - gap] > temp; j -= gap) {
+                arr[j] = arr[j - gap];
+            }
+            arr[j] = temp;
+        }
+    }
+}
+
+int main() {
+    int n;
+    cout << "Enter number of elements: ";
+    cin >> n;
+
+    vector<int> arr(n);
+    cout << "Enter elements: ";
+    for (int i = 0; i < n; i++)
+        cin >> arr[i];
+
+    shellSort(arr);
+
+    cout << "Sorted array: ";
+    for (int x : arr)
+        cout << x << " ";
+    cout << endl;
+
+    return 0;
+}