Create Insertion_sort.java

Java_Programs_for_beginners/Insertion_sort.java

@@ -0,0 +1,62 @@
+// Java program for implementation of Insertion Sort 
+
+class InsertionSort { 
+ /*Function to sort array using insertion sort*/
+ void sort(int arr[]) 
+ { 
+ int n = arr.length; 
+ for (int i = 1; i < n; ++i) { 
+ int key = arr[i]; 
+ 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]; 
+ j = j - 1; 
+ } 
+ arr[j + 1] = key; 
+ } 
+ } 
+
+ /* A utility function to print array of size n*/
+ static void printArray(int arr[]) 
+ { 
+ int n = arr.length; 
+ for (int i = 0; i < n; ++i) 
+ System.out.print(arr[i] + " "); 
+
+ System.out.println(); 
+ } 
+
+ // Driver method 
+ public static void main(String args[]) 
+ { 
+ int arr[] = { 12, 11, 13, 5, 6 }; 
+
+ InsertionSort ob = new InsertionSort(); 
+ ob.sort(arr); 
+
+ printArray(arr); 
+ } 
+}
+
+
+Example:
+12, 11, 13, 5, 6
+
+Let us loop for i = 1 (second element of the array) to 4 (last element of the array)
+
+i = 1. Since 11 is smaller than 12, move 12 and insert 11 before 12
+11, 12, 13, 5, 6
+
+i = 2. 13 will remain at its position as all elements in A[0..I-1] are smaller than 13
+11, 12, 13, 5, 6
+
+i = 3. 5 will move to the beginning and all other elements from 11 to 13 will move one position ahead of their current position.
+5, 11, 12, 13, 6
+
+i = 4. 6 will move to position after 5, and elements from 11 to 13 will move one position ahead of their current position.
+5, 6, 11, 12, 13
+