【leetcode刷题笔记】Reverse Words in a String

Given an input string, reverse the string word by word.

For example,
Given s = "the sky is blue",
return "blue is sky the".

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题解：用栈就行了

代码：

class Solution {
public:
    void reverseWords(string &s) {
        stack<string>st;
        string temp = "";

        for(int i = 0;i <= s.length();i++){
            if(i == s.length())
            {
                st.push(temp);
            }
            else if(s[i] != ' '){
                temp += s[i];
            }
            else
            {
                if(temp != ""){
                    st.push(temp);
                    temp = "";
                }
            }
        }
        s = "";
        while(!st.empty()){
            if(st.top() != " ")
                s += st.top();
            st.pop();
            if(!st.empty() && s != ""){
                s += " ";
            }
        }
    }
};