leetcode-Reverse Words in a String

Reverse Words in a String

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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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此题要翻转一个字符串中的单词，属于比較简单的字符串处理题。

C++：
直接扫描字符串把遇到的单词插入到deque的前面。扫描完把deque容器内的单词拼起来就可以。

class Solution {
public:
    void reverseWords(string &s) {
        deque<string> ds;
        int b, i(0), len(s.size());
        while (i < len) {
            while (i<len && s[i]==' ') ++i;
            if (i == len) break;
            b = i;
            while (i<len && s[i]!=' ') ++i;
            ds.push_front(s.substr(b, i-b));
        }
        s = "";
        if (ds.empty()) return;
        s += ds[0];
        for (i=1; i<ds.size(); ++i) s += " " + ds[i];
        
    }
};

可是假设加上限制呢？比方不能利用额外线性空间复杂度，又该怎样解呢？临时还没想到。

Python：
Python处理更简单了。三行代码就搞定了。

class Solution:
    # @param s, a string
    # @return a string
    def reverseWords(self, s):
        ss = s.split()
        ss.reverse()
        return " ".join(ss)