Leetcode 186 Flip the word II in the string (2022.07.05)

Given a string , Flip each word in the string one by one .

Example ：

Input : [“t”,“h”,“e”," “,“s”,“k”,“y”,” “,“i”,“s”,” “,“b”,“l”,“u”,“e”]
Output : [“b”,“l”,“u”,“e”,” “,“i”,“s”,” “,“s”,“k”,“y”,” ",“t”,“h”,“e”]

Be careful ：

A word is defined as a series of characters that do not contain spaces
The input string will not contain leading or trailing spaces
Words are always separated from each other by a single space
Advanced ： Use O(1) In situ solution of extra space complexity .

source ： Power button （LeetCode）
link ：https://leetcode.cn/problems/reverse-words-in-a-string-ii

Method 1 ： Double pointer

C++ Submission ：

class Solution {
    
public:
    void reverseWords(vector<char>& s) {
    
        int left = 0;
        int right = 0;
        int len = s.size();
        while (right < len) {
    
            if (s[right] == ' ') {
    
                Swap(s, left, right - 1);
                right++;
                left = right;
            } else {
    
                right++;
            }
        }
        Swap(s, left, len - 1);
        Swap(s, 0, len - 1);
    }
    void Swap(vector<char>& s, int left, int right) {
    
        char temp;
        while (left < right) {
    
            temp = s[left];
            s[left] = s[right];
            s[right] = temp;
            left++;
            right--;
        }
    }
};