04. Non-Decreasing Subsequence / JavaScript

EvgeniJD 35 Точки

04. Non-Decreasing Subsequence / JavaScript

Здравейте, някой може ли да ми покаже как да реша задачата с .filter();

4.Non-Decreasing Subsequence

Write a function that extracts only those numbers that form a non-decreasing subsequence. In other words, you start from the first element and continue to the end of the given array of numbers. Any number which is LESS THAN the current biggest one is ignored, alternatively if it’s equal or higher than the current biggest one you set it as the current biggest one and you continue to the next number.

Input

The input comes as array of numbers.

Output

The output is the processed array after the filtration, which should be a non-decreasing subsequence. The elements should be printed on one line, separated by a single space.

Examples

Input	Output
[ 1, 3, 8, 4, 10, 12, 3, 2, 24]	1 3 8 10 12 24
[ 1, 2, 3, 4]	1 2 3 4
[ 20, 3, 2, 15, 6, 1]	20

Hints

The Array.filter() built-in function might help you a lot with this problem.

Тагове:

04/02/2020 23:40:33 JavaScript Fundamentals

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willystyle 2472 Точки

Best Answer

function solve(arr) {
    console.log(arr.filter((el, index) => el >= Math.max(...arr.slice(0, index))).join(' '));
}

или може би по-ефективно е:

function solve3(arr) {
    let max = arr[0];
    let result = arr.filter(el => {
        if (el >= max) {
            max = el;
        }
        return el >= max;
    });
    console.log(result.join(' '));
}

05/02/2020 11:23:26 05/02/2020 11:33:44

EvgeniJD 35 Точки

Какво значат трите точки преди slice? На моето ниво второто решение е по-четимо :) Благодаря ти, отново!

06/02/2020 23:28:37

willystyle 2472 Точки

това е spread operator, превръща масив в iterable: https://developer.mozilla.org/bg/docs/Web/JavaScript/Reference/Operators/%D1%80%D0%B0%D0%B7%D0%BF%D1%80%D0%B5%D0%B4%D0%B5%D0%BB%D1%8F%D1%89_%D1%81%D0%B8%D0%BD%D1%82%D0%B0%D0%BA%D1%81%D0%B8%D1%81

07/02/2020 10:52:18

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