Reverse Words in a String II

LeetCode #186

Description:

Given an input string, reverse the string word by word. A word is defined as a sequence of non-space characters.

The input string does not contain leading or trailing spaces and the words are always separated by a single space.

Example:

Note

Idea:

操，比Reverse words in a string简单多了！

Code:

    void reverseWords(string &s) {
        int i=0, j; // left and right of one word
        int icurr=0; // current copy position
        int n=s.size();

        while(i!=n){
            while(i!=n && s[i]==' '){ // Until non space is found
                ++i;
            }
            j=i;
            while(j!=n && s[j]!=' '){ // Until space is found
                j++;
            }

            if(i!=n){
                reverseSingleWord(s, i, j-1); // reverse one word
            }

            while(i!=j){ // Copy one word
                s[icurr++] = s[i++];
            }
            icurr++;

        }

        reverseSingleWord(s, 0, s.size()-1); // reverse the whole sentence

    }

    void reverseSingleWord(string &s, int i, int j){
        while(i<j){
            swap(s[i], s[j]);
            i++;
            j--;
        }
    }