2018-10-10 18:03:03 -04:00
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---
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id: 587d825b367417b2b2512c8b
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2020-12-16 00:37:30 -07:00
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title: 从最大堆中删除元素
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2018-10-10 18:03:03 -04:00
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challengeType: 1
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videoUrl: ''
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2021-01-13 03:31:00 +01:00
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dashedName: remove-an-element-from-a-max-heap
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2018-10-10 18:03:03 -04:00
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---
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2020-12-16 00:37:30 -07:00
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# --description--
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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现在我们可以向堆中添加元素,让我们看看如何删除元素。删除和插入元素都需要类似的逻辑。在最大堆中,您通常需要删除最大值,因此这只需要从树的根中提取它。这将破坏我们树的堆属性,因此我们必须以某种方式重新建立它。通常,对于最大堆,这可以通过以下方式完成:将堆中的最后一个元素移动到根位置。如果root的子节点大于它,则将root与较大值的子节点交换。继续交换,直到父级大于两个子级,或者到达树中的最后一级。说明:向我们的最大堆添加一个名为remove的方法。此方法应返回已添加到最大堆的最大值,并将其从堆中删除。它还应该重新排序堆,以便保持堆属性。删除元素后,堆中剩余的下一个最大元素应该成为根。此处再次添加插入方法。
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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# --hints--
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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存在MaxHeap数据结构。
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2018-10-10 18:03:03 -04:00
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```js
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2020-12-16 00:37:30 -07:00
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assert(
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(function () {
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var test = false;
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if (typeof MaxHeap !== 'undefined') {
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test = new MaxHeap();
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}
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return typeof test == 'object';
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})()
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);
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```
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MaxHeap有一个名为print的方法。
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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```js
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assert(
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(function () {
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var test = false;
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if (typeof MaxHeap !== 'undefined') {
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test = new MaxHeap();
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} else {
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return false;
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}
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return typeof test.print == 'function';
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})()
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);
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2018-10-10 18:03:03 -04:00
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```
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2020-12-16 00:37:30 -07:00
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MaxHeap有一个名为insert的方法。
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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```js
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assert(
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(function () {
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var test = false;
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if (typeof MaxHeap !== 'undefined') {
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test = new MaxHeap();
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} else {
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return false;
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}
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return typeof test.insert == 'function';
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})()
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);
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```
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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MaxHeap有一个名为remove的方法。
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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```js
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assert(
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(function () {
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var test = false;
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if (typeof MaxHeap !== 'undefined') {
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test = new MaxHeap();
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} else {
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return false;
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}
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return typeof test.remove == 'function';
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})()
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);
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```
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2018-10-10 18:03:03 -04:00
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2020-12-16 00:37:30 -07:00
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remove方法从最大堆中删除最大元素,同时保持最大堆属性。
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2018-10-10 18:03:03 -04:00
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```js
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2020-12-16 00:37:30 -07:00
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assert(
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(function () {
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var test = false;
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if (typeof MaxHeap !== 'undefined') {
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test = new MaxHeap();
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} else {
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return false;
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}
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test.insert(30);
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test.insert(300);
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test.insert(500);
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test.insert(10);
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let result = [];
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result.push(test.remove());
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result.push(test.remove());
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result.push(test.remove());
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result.push(test.remove());
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return result.join('') == '5003003010';
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})()
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);
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2018-10-10 18:03:03 -04:00
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```
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2020-08-13 17:24:35 +02:00
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2021-01-13 03:31:00 +01:00
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# --seed--
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## --seed-contents--
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```js
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var MaxHeap = function() {
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this.heap = [null];
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this.insert = (ele) => {
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var index = this.heap.length;
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var arr = [...this.heap];
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arr.push(ele);
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while (ele > arr[Math.floor(index / 2)] && index > 1) {
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arr[index] = arr[Math.floor(index / 2)];
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arr[Math.floor(index / 2)] = ele;
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index = arr[Math.floor(index / 2)];
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}
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this.heap = arr;
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}
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this.print = () => {
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return this.heap.slice(1);
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}
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// Only change code below this line
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// Only change code above this line
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};
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```
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2020-12-16 00:37:30 -07:00
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# --solutions--
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2021-01-13 03:31:00 +01:00
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```js
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// solution required
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```
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