@ickb/utils/dist/heap.js

General utilities built on top of CCC

export class MinHeap {
    constructor(lessFunc, heap) {
        Object.defineProperty(this, "lessFunc", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: lessFunc
        });
        Object.defineProperty(this, "heap", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: heap
        });
    }
    static from(lessFunc, unordered = []) {
        const heap = new MinHeap(lessFunc, [...unordered]);
        const n = heap.len();
        for (let i = (n >> 1) - 1; i >= 0; i--) {
            heap.down(i, n);
        }
        return heap;
    }
    less(i, j) {
        return this.lessFunc(this.heap, i, j);
    }
    len() {
        return this.heap.length;
    }
    isEmpty() {
        return this.heap.length === 0;
    }
    push(x) {
        this.heap.push(x);
        this.up(this.len() - 1);
    }
    pop() {
        if (this.len() === 0) {
            return;
        }
        const n = this.len() - 1;
        this.swap(0, n);
        this.down(0, n);
        return this.heap.pop();
    }
    remove(i) {
        if (this.len() <= i) {
            return;
        }
        const n = this.len() - 1;
        if (n != i) {
            this.swap(i, n);
            if (!this.down(i, n)) {
                this.up(i);
            }
        }
        return this.pop();
    }
    fix(i) {
        if (this.len() <= i) {
            return;
        }
        if (!this.down(i, this.len())) {
            this.up(i);
        }
    }
    up(j) {
        while (true) {
            const i = (j - 1) >> 1;
            if (i == j || !this.less(j, i)) {
                break;
            }
            this.swap(i, j);
            j = i;
        }
    }
    down(i0, n) {
        let i = i0;
        while (true) {
            const j1 = (i << 1) + 1;
            if (j1 >= n || j1 < 0) {
                break;
            }
            let j = j1;
            const j2 = j1 + 1;
            if (j2 < n && this.less(j2, j1)) {
                j = j2;
            }
            if (!this.less(j, i)) {
                break;
            }
            this.swap(i, j);
            i = j;
        }
        return i > i0;
    }
    swap(i, j) {
        [this.heap[i], this.heap[j]] = [this.heap[j], this.heap[i]];
    }
}
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