120 lines
2.4 KiB
JavaScript
120 lines
2.4 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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// Binary min-heap implementation used for priority queue.
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// Implementation is stable, i.e. push time is considered for equal priorities
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class Heap {
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constructor() {
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this.heap = [];
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this.pushCount = Number.MIN_SAFE_INTEGER;
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}
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get length() {
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return this.heap.length;
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}
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empty() {
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this.heap = [];
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return this;
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}
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percUp(index) {
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let p;
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while (index > 0 && smaller(this.heap[index], this.heap[p = parent(index)])) {
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let t = this.heap[index];
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this.heap[index] = this.heap[p];
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this.heap[p] = t;
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index = p;
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}
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}
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percDown(index) {
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let l;
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while ((l = leftChi(index)) < this.heap.length) {
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if (l + 1 < this.heap.length && smaller(this.heap[l + 1], this.heap[l])) {
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l = l + 1;
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}
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if (smaller(this.heap[index], this.heap[l])) {
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break;
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}
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let t = this.heap[index];
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this.heap[index] = this.heap[l];
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this.heap[l] = t;
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index = l;
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}
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}
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push(node) {
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node.pushCount = ++this.pushCount;
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this.heap.push(node);
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this.percUp(this.heap.length - 1);
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}
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unshift(node) {
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return this.heap.push(node);
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}
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shift() {
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let [top] = this.heap;
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this.heap[0] = this.heap[this.heap.length - 1];
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this.heap.pop();
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this.percDown(0);
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return top;
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}
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toArray() {
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return [...this];
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}
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*[Symbol.iterator]() {
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for (let i = 0; i < this.heap.length; i++) {
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yield this.heap[i].data;
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}
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}
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remove(testFn) {
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let j = 0;
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for (let i = 0; i < this.heap.length; i++) {
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if (!testFn(this.heap[i])) {
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this.heap[j] = this.heap[i];
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j++;
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}
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}
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this.heap.splice(j);
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for (let i = parent(this.heap.length - 1); i >= 0; i--) {
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this.percDown(i);
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}
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return this;
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}
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}
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exports.default = Heap;
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function leftChi(i) {
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return (i << 1) + 1;
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}
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function parent(i) {
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return (i + 1 >> 1) - 1;
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}
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function smaller(x, y) {
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if (x.priority !== y.priority) {
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return x.priority < y.priority;
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} else {
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return x.pushCount < y.pushCount;
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}
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}
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module.exports = exports.default; |