From d93ee0de2dfaa848e1123304bcb6ac52c53723b0 Mon Sep 17 00:00:00 2001
From: Du Yuanchao <shellhub.me@gmail.com>
Date: Mon, 12 Apr 2021 18:58:24 +0800
Subject: [PATCH] udpate insertion sort (#2176)

* udpate insertion sort

* Formatted with Google Java Formatter

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
---
 Sorts/InsertionSort.java | 44 ++++++++++++++--------------------------
 1 file changed, 15 insertions(+), 29 deletions(-)

diff --git a/Sorts/InsertionSort.java b/Sorts/InsertionSort.java
index d2dd1c93e..2114067ab 100644
--- a/Sorts/InsertionSort.java
+++ b/Sorts/InsertionSort.java
@@ -3,53 +3,39 @@ package Sorts;
 import static Sorts.SortUtils.less;
 import static Sorts.SortUtils.print;
 
-/**
- * @author Varun Upadhyay (https://github.com/varunu28)
- * @author Podshivalov Nikita (https://github.com/nikitap492)
- */
 class InsertionSort implements SortAlgorithm {
 
   /**
-   * This method implements the Generic Insertion Sort Sorts the array in increasing order
+   * Generic insertion sort algorithm in increasing order.
    *
-   * @param array The array to be sorted
+   * @param array the array to be sorted.
+   * @param <T> the class of array.
+   * @return sorted array.
    */
   @Override
   public <T extends Comparable<T>> T[] sort(T[] array) {
-    for (int j = 1; j < array.length; j++) {
-
-      // Picking up the key(Card)
-      T key = array[j];
-      int i = j - 1;
-
-      while (i >= 0 && less(key, array[i])) {
-        array[i + 1] = array[i];
-        i--;
+    for (int i = 1; i < array.length; i++) {
+      T insertValue = array[i];
+      int j;
+      for (j = i - 1; j >= 0 && less(insertValue, array[j]); j--) {
+        array[j + 1] = array[j];
+      }
+      if (j != i - 1) {
+        array[j + 1] = insertValue;
       }
-      // Placing the key (Card) at its correct position in the sorted subarray
-      array[i + 1] = key;
     }
     return array;
   }
 
-  // Driver Program
+  /** Driver Code */
   public static void main(String[] args) {
-    // Integer Input
     Integer[] integers = {4, 23, 6, 78, 1, 54, 231, 9, 12};
-
     InsertionSort sort = new InsertionSort();
-
     sort.sort(integers);
+    print(integers); /* [1, 4, 6, 9, 12, 23, 54, 78, 231] */
 
-    // Output => 1 4 6 9 12 23 54 78 231
-    print(integers);
-
-    // String Input
     String[] strings = {"c", "a", "e", "b", "d"};
-
     sort.sort(strings);
-
-    // Output => a	b	c	d	e
-    print(strings);
+    print(strings); /* [a, b, c, d, e] */
   }
 }