Coding problem · Easy · Basics

Reverse the Words

Easy Algorithms & data structures

Given a sentence s of words separated by single spaces, return the words in reverse order.

Example 1

Input: s = "the sky is blue"
Output: "blue is sky the"

Example 2

Input: s = "hello"
Output: "hello"

Hints

Hint 1

Split into words, reverse the list, join with spaces.

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Solution and explanation

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Time O(n) · Space O(n)

Split on spaces, reverse the resulting list of words, and join it back. The characters inside each word stay in order.

Reference solution

function reverseWords(s) {
  return s.split(' ').reverse().join(' ');
}

function reverseWords(s: string): string {
  return s.split(' ').reverse().join(' ');
}

def reverse_words(s: str) -> str:
    return ' '.join(reversed(s.split(' ')))

<?php

function reverseWords(string $s): string
{
    return implode(' ', array_reverse(explode(' ', $s)));
}

class Solution {
    public String reverseWords(String s) {
        java.util.List<String> words = java.util.Arrays.asList(s.split(" "));
        java.util.Collections.reverse(words);
        return String.join(" ", words);
    }
}

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