leetcode 151. Reverse Words in a String 字符串分割逆序 + stringstream分割字符串

Love The Way You Lie 2022-06-08 06:25 165阅读 0赞

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

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

Update (2015-02-12):  
For C programmers: Try to solve it in-place in O(1) space.

对于Java实现，直接分割字符串然后逆序即可。

代码如下：

public class Solution 
    {
        public String reverseWords(String s) 
        {
            if(s==null || s.length()<=0)
                return s;
    
            s=s.trim();
            String []res=s.split("\\s+");
            if(res.length<=1)
                return s;
    
            StringBuilder builder=new StringBuilder();
            builder.append(res[res.length-1]);
            for(int i=res.length-2;i>=0;i--)
                builder.append(" "+res[i]);
            return builder.toString();
        }
    }

下面是C++的做法，就是做一个字符串分割，直接使用stringstream来做分割即可，很好用的

代码如下：

#include <iostream>
    #include <vector>
    #include <map>
    #include <unordered_map>
    #include <set>
    #include <unordered_set>
    #include <queue>
    #include <stack>
    #include <string>
    #include <climits>
    #include <algorithm>
    #include <sstream>
    #include <functional>
    #include <bitset>
    #include <numeric>
    #include <cmath>
    #include <regex>
    
    using namespace std;
    
    
    
    
    class Solution 
    {
    public:
        void reverseWords(string &s) 
        {
            stringstream ss(s);
            vector<string> res;
            string tmp = "";
            while (ss >> tmp)
                res.push_back(tmp);
    
            if (res.size() ==0)
                s = "";
            else
            {
                s = res[res.size() - 1];
                for (int i = res.size() - 2; i >= 0; i--)
                    s += " " + res[i];
            }
        }
    };