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补充非递归方式堆化 #40

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补充非递归方式堆化 #40

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32 changes: 30 additions & 2 deletions 7.heapSort.md
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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) {
Expand Down
32 changes: 30 additions & 2 deletions src/java/main/HeapSort.java
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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];
Expand Down