Add Insertion Sort algorithm in Java with comments

Farheen Shabbir Shaikh · Farheen Shabbir Shaikh · commit c0601d005ae5 · 2025-06-08T18:26:12.000-07:00
diff --git a/Sorting/InsertionSort.java b/Sorting/InsertionSort.java
@@ -0,0 +1,33 @@
+/**
+ * InsertionSort.java
+ * This program implements the Insertion Sort algorithm.
+ * Time Complexity: O(n^2) in worst case, O(n) in best case (already sorted).
+ */
+
+public class InsertionSort {
+
+    public static void insertionSort(int[] arr) {
+        // Loop from the second element to the end
+        for (int i = 1; i < arr.length; i++) {
+            int key = arr[i];  // Store the current element to be inserted
+            int j = i - 1;
+
+            // Move elements of arr[0..i-1], that are greater than key,
+            // to one position ahead of their current position
+            while (j >= 0 && arr[j] > key) {
+                arr[j + 1] = arr[j];  // Shift element to the right
+                j = j - 1;
+            }
+            arr[j + 1] = key;  // Insert the key into its correct position
+        }
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {29, 10, 14, 37, 13};
+        insertionSort(arr);
+        System.out.println("Sorted array:");
+        for (int num : arr) {
+            System.out.print(num + " ");
+        }
+    }
+}
