wp-node-quicksort

wp-node-quicksort.js

'use strict';
const quickSort = (arr, dimension, left = 0, right = arr.length - 1) => {
    const len = arr.length; let index;
    if (len > 1) {
        index = partition(arr, dimension, left, right);
        if(left < index - 1) quickSort(arr, dimension, left, index - 1);
        if(index < right) quickSort(arr, dimension, index, right);
    }
    return arr;
};

const partition = (arr, dimension, left, right) => {
    const middle = Math.floor((right + left) / 2), pivot = arr[middle];
    let i=left, j=right;
    while(i <= j) {
        while(arr[i][dimension] > pivot[dimension]) { i++ }
        while(arr[j][dimension] < pivot[dimension]) { j-- }
        if(i <= j) { [arr[i], arr[j]] = [arr[j], arr[i]]; i++; j-- }
    }
    return i;
};

const fs = require('fs');
const startTime = Date.now();
const log = (msg) => setImmediate(() => { process.stdout.write(msg); });
fs.readFile("/dev/stdin", 'utf8', (err, text) => {
    const map = {}, unsorted = [], lines = text.split("\n");
    for (let i=0; i<lines.length; i++) {
        const words = lines[i].split(' ');
        for (let j=0; j<words.length; j++) {
            if (words[j].length === 0) continue;
            if (typeof map[words[j]] === 'undefined') map[words[j]] = 1;
            else map[words[j]]++;
        }
    }
    for (let word in map) unsorted.push([word, map[word]]);
    const sorted = quickSort(unsorted, 1);
    for (let i=0; i<sorted.length; i++) log(`${sorted[i][0]}: ${sorted[i][1]}\n`);
    const endTime = Date.now();
    log(`Time: ${endTime - startTime}ms Items: ${sorted.length}\n`);
});