Update .gitignore

This commit is contained in:
Yudong Jin 2023-01-08 20:30:09 +08:00
parent 230c7723d5
commit e8f7d8f8ba
2 changed files with 1 additions and 118 deletions

4
.gitignore vendored
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@ -4,6 +4,7 @@
# Editor # Editor
.vscode/ .vscode/
.idea/ .idea/
hello-algo.iml
# mkdocs files # mkdocs files
site/ site/
@ -13,6 +14,3 @@ docs/overrides/
# python files # python files
__pycache__ __pycache__
# in-progress articles
docs/chapter_heap

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@ -1,115 +0,0 @@
/**
* File: my_heap.java
* Created Time: 2023-01-07
* Author: Krahets (krahets@163.com)
*/
package chapter_heap;
import include.*;
import java.util.*;
class MaxHeap {
private List<Integer> heap;
public MaxHeap() {
heap = new ArrayList<>();
}
public MaxHeap(List<Integer> nums) {
// 将元素拷贝至堆中
heap = new ArrayList<>(nums);
// 堆化除叶结点外的其他所有结点
for (int i = parent(size() - 1); i >= 0; i--) {
heapify(i);
}
}
/* 获取左子结点 */
private int left(int i) {
return 2 * i + 1;
}
/* 获取右子结点 */
private int right(int i) {
return 2 * i + 2;
}
/* 获取父结点 */
private int parent(int i) {
return (i - 1) / 2;
}
/* 交换元素 */
private void swap(int i, int j) {
int tmp = heap.get(i);
heap.set(i, j);
heap.set(j, tmp);
}
public int size() {
return heap.size();
}
public boolean isEmpty() {
return size() == 0;
}
/* 获取堆顶元素 */
public int peek() {
return heap.get(0);
}
/* 元素入堆 */
public void push(int val) {
heap.add(val);
// 从底至顶堆化
int i = size();
while (true) {
int p = parent(i);
if (p < 0 || heap.get(i) > heap.get(p))
break;
swap(i, p);
i = p;
}
}
/* 元素出堆 */
public int poll() {
// 判空处理
if (isEmpty())
throw new EmptyStackException();
// 交换根结点与右下角即最后一个结点
swap(0, size() - 1);
// 删除结点
int val = heap.remove(size() - 1);
// 从顶至底堆化
heapify(0);
// 返回堆顶元素
return val;
}
/* 从结点 i 开始,从顶至底堆化 */
private void heapify(int i) {
while (true) {
// 判断结点 i, l, r 中的最大结点记为 ma
int l = left(i), r = right(i), ma = i;
if (heap.get(l) > heap.get(ma)) ma = l;
if (heap.get(r) > heap.get(ma)) ma = r;
// 若结点 i 最大则无需继续堆化跳出
if (ma == i) break;
// 交换结点 i 与结点 max
swap(i, ma);
// 循环向下堆化
i = ma;
}
}
}
public class my_heap {
public static void main(String[] args) {
}
}