151.ReverseWords.cs

// 151. Reverse Words in a String

// Given an input string s, reverse the order of the words.
// A word is defined as a sequence of non-space characters. The words in s will be separated by at least one space.
// Return a string of the words in reverse order concatenated by a single space.
// Note that s may contain leading or trailing spaces or multiple spaces between two words. The returned string should only have a single space separating the words. Do not include any extra spaces.

// Example 1:
// Input: s = "the sky is blue"
// Output: "blue is sky the"
// Example 2:
// Input: s = "  hello world  "
// Output: "world hello"
// Explanation: Your reversed string should not contain leading or trailing spaces.
// Example 3:
// Input: s = "a good   example"
// Output: "example good a"
// Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.

public class Solution {
    public string ReverseWords(string s) {
        string[] words = s.Split(" ");
        Array.Reverse(words);
        List<string> lWords = new List<string>(words);
        lWords.RemoveAll(x => x == "");
        words = lWords.ToArray();
        return string.Join(" ", words);
    }
}