From 7afb8102a2c894ea759bf24c3ec72d7f8cc1b8df Mon Sep 17 00:00:00 2001
From: qrqhuangcy <qrqhuangcy@hotmail.com>
Date: Mon, 4 May 2020 04:54:52 +0800
Subject: [PATCH] =?UTF-8?q?=E8=A1=A5=E5=85=85=E9=9D=9E=E9=80=92=E5=BD=92?=
 =?UTF-8?q?=E6=96=B9=E5=BC=8F=E5=A0=86=E5=8C=96?=
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---
 7.heapSort.md               | 32 ++++++++++++++++++++++++++++++--
 src/java/main/HeapSort.java | 32 ++++++++++++++++++++++++++++++--
 2 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/7.heapSort.md b/7.heapSort.md
index 394d929..1195b2a 100644
--- a/7.heapSort.md
+++ b/7.heapSort.md
@@ -176,7 +176,10 @@ public class HeapSort implements IArraySort {
         }
     }
 
-    private void heapify(int[] arr, int i, int len) {
+    /**
+     * 1. 递归方式堆化
+     */
+    private void heapifyRecursive(int[] arr, int i, int len) {
         int left = 2 * i + 1;
         int right = 2 * i + 2;
         int largest = i;
@@ -191,8 +194,33 @@ public class HeapSort implements IArraySort {
 
         if (largest != i) {
             swap(arr, i, largest);
-            heapify(arr, largest, len);
+            heapifyRecursive(arr, largest, len);
+        }
+    }
+
+    /**
+     * 2. 非递归方式堆化
+     */
+    private void heapify(int[] arr, int i, int len) {
+        int tmp = arr[i];
+
+        for (int j = i * 2 + 1; j < len; j = j * 2 + 1) {
+            //比较左右子结点谁更大
+            if (j + 1 < len && arr[j] < arr[j + 1]) {
+                j++;
+            }
+            //如果子节点没父节点大，跳过
+            if (arr[j] <= tmp) {
+                break;
+            } else {
+                //将子节点的值赋给父节点
+                arr[i] = arr[j];
+                //升级为新的父节点
+                i = j;
+            }
         }
+
+        arr[i] = tmp;
     }
 
     private void swap(int[] arr, int i, int j) {
diff --git a/src/java/main/HeapSort.java b/src/java/main/HeapSort.java
index 6e9dcfe..b8c04cf 100644
--- a/src/java/main/HeapSort.java
+++ b/src/java/main/HeapSort.java
@@ -28,7 +28,10 @@ private void buildMaxHeap(int[] arr, int len) {
         }
     }
 
-    private void heapify(int[] arr, int i, int len) {
+    /**
+     * 递归方式堆化
+     */
+    private void heapifyRecursive(int[] arr, int i, int len) {
         int left = 2 * i + 1;
         int right = 2 * i + 2;
         int largest = i;
@@ -43,10 +46,35 @@ private void heapify(int[] arr, int i, int len) {
 
         if (largest != i) {
             swap(arr, i, largest);
-            heapify(arr, largest, len);
+            heapifyRecursive(arr, largest, len);
         }
     }
 
+    /**
+     * 非递归方式堆化
+     */
+    private void heapify(int[] arr, int i, int len) {
+        int tmp = arr[i];
+
+        for (int j = i * 2 + 1; j < len; j = j * 2 + 1) {
+            //比较左右子结点谁更大
+            if (j + 1 < len && arr[j] < arr[j + 1]) {
+                j++;
+            }
+            //如果子节点没父节点大，跳过
+            if (arr[j] <= tmp) {
+                break;
+            } else {
+                //将子节点的值赋给父节点
+                arr[i] = arr[j];
+                //升级为新的父节点
+                i = j;
+            }
+        }
+
+        arr[i] = tmp;
+    }
+
     private void swap(int[] arr, int i, int j) {
         int temp = arr[i];
         arr[i] = arr[j];