120 lines
3.4 KiB
JavaScript
120 lines
3.4 KiB
JavaScript
/**
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* 优先队列的 堆实现
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*/
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class HeapNode {
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constructor(num, item) {
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this.sortNum = num;
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this.content = item;
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}
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}
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class Heap {
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constructor(arr = []) {
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this.PRIVATE = {
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swap(arr, i, j) {
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let temp = arr[i]
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arr[i] = arr[j]
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arr[j] = temp
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},
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//从point往下 堆化
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heapify(point = 1) {
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let { swap, store } = this;
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while (true) {
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let lPoint = point * 2;
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let rPoint = point * 2 + 1;
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if (store[lPoint] && store[point].sortNum < store[lPoint].sortNum) {
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swap(store, point, lPoint);
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point = lPoint;
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continue
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}
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if (store[rPoint] && store[point].sortNum < store[rPoint].sortNum) {
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swap(store, point, rPoint);
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point = rPoint;
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continue
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}
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break;
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}
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},
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store: [null].concat(arr)
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}
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//建堆
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//从最后一个非子叶节点遍历
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for (let i = (this.PRIVATE.store.length / 2 | 0); i > 1; i--) {
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this.PRIVATE.heapify(i);
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}
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}
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insert(node) {
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let store = this.PRIVATE.store;
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let HeapUtil = this.PRIVATE;
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store.push(node);
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let point = store.length - 1;
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let sub = point / 2 | 0;
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while (sub > 0 && store[point].sortNum > store[sub].sortNum) { // 自下往上堆化
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HeapUtil.swap(store, point, sub); // swap()函数作用：交换下标为i和i/2的两个元素
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point = sub;
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sub = sub / 2 | 0;
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}
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}
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getMax() {
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let store = this.PRIVATE.store;
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let point = store.length - 1;
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if (point === 0) {
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return null;
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}
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let HeapUtil = this.PRIVATE;
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//最大与末尾元素交换
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HeapUtil.swap(store, point, 1);
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let max = store.pop();
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HeapUtil.heapify();
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return max;
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}
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}
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function HeapTest() {
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let maxHeap = new Heap();
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console.log('偶数个')
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maxHeap.insert(new HeapNode(2, 'c'))
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maxHeap.insert(new HeapNode(1, 'c'))
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maxHeap.insert(new HeapNode(7, 'a'))
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maxHeap.insert(new HeapNode(4, 'c'))
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console.log('check:', isHeapArr(maxHeap.PRIVATE.store));
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console.log('奇数个')
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maxHeap.insert(new HeapNode(5, 'b'))
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maxHeap.insert(new HeapNode(6, 'c'))
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maxHeap.insert(new HeapNode(10, 'a'))
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console.log('check:', isHeapArr(maxHeap.PRIVATE.store));
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console.log('获取最大值：', maxHeap.getMax());
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console.log('check:', isHeapArr(maxHeap.PRIVATE.store));
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console.log('获取最大值：', maxHeap.getMax());
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console.log('check:', isHeapArr(maxHeap.PRIVATE.store));
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}
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function createTest() {
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console.log('随机创建测试:')
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let arr = [];
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let i = 0
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while (i <= 10) {
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const num = Math.floor(Math.random() * 100)
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arr.push(new HeapNode(num, i))
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i++
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}
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let heap = new Heap(arr);
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console.log('check:', isHeapArr(heap.PRIVATE.store))
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}
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function isHeapArr(arr) {
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for (let i = 1; i < arr.length; i++) {
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let p = arr[i];
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let l = arr[i * 2];
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let r = arr[i * 2 + 1];
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if (l > p || r > p) {
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return false;
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}
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}
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return true;
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}
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