hd-utils/lib/utils/array/heapSort.js

A handy utils for modern JS developers

/**
 * @description an implementation for heapSort algorithm, it will sort an array of numbers or strings.
 * @example heapSort([3,2,1]) // [1,2,3]
 */
export default function heapSort(arr) {
    buildMaxHeap(arr);
    for (let i = arr.length - 1; i > 0; i--) {
        [arr[0], arr[i]] = [arr[i], arr[0]];
        heapify(arr, i, 0);
    }
    return arr;
}
function buildMaxHeap(arr) {
    const n = arr.length;
    for (let i = Math.floor(n / 2) - 1; i >= 0; i--) {
        heapify(arr, n, i);
    }
}
function heapify(arr, n, i) {
    let largest = i;
    const left = 2 * i + 1;
    const right = 2 * i + 2;
    if (left < n && arr[left] > arr[largest]) {
        largest = left;
    }
    if (right < n && arr[right] > arr[largest]) {
        largest = right;
    }
    if (largest !== i) {
        [arr[i], arr[largest]] = [arr[largest], arr[i]];
        heapify(arr, n, largest);
    }
}