68 lines
1.5 KiB
JavaScript
68 lines
1.5 KiB
JavaScript
class MinHeap {
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constructor(valueFunc=(a) => a) {
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this.valueFunc_ = valueFunc;
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this.data_ = [];
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}
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push(...vals) {
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for (let val of vals) {
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this.data_.push(val);
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this.bubbleUp_();
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}
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}
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pop() {
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let min = this.data_[0];
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if (this.data_.length > 1) {
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this.data_[0] = this.data_.pop();
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this.bubbleDown_();
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} else {
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this.data_.length = 0;
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}
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return min;
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}
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bubbleUp_() {
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for (let idx = this.data_.length - 1; idx > 0;) {
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let parent = Math.floor((idx + 1) / 2) - 1;
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if (this.valueFunc_(this.data_[parent]) >
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this.valueFunc_(this.data_[idx])) {
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[this.data_[parent], this.data_[idx]] =
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[this.data_[idx], this.data_[parent]];
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}
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idx = parent;
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}
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}
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bubbleDown_() {
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for (let idx = 0;;) {
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let children = [
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(idx + 1) * 2,
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(idx + 1) * 2 - 1,
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];
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let toSwap = idx;
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// Find the minimum value of the current node and its two children
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for (let child of children) {
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if (this.data_[child] != undefined &&
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this.valueFunc_(this.data_[child]) <
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this.valueFunc_(this.data_[toSwap])) {
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toSwap = child;
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}
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}
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if (toSwap == idx) {
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// Current node is smaller than both children; tree is correct
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break;
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}
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[this.data_[toSwap], this.data_[idx]] =
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[this.data_[idx], this.data_[toSwap]];
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idx = toSwap;
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}
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}
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};
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