[LeetCode 第3题] -- Reverse Words in a String

题目链接: Reverse Words in s String

题目意思: 给定一个字符串，要求把字符串中的"单词"反转

                1. 所谓"单词"指的的连续的非空白字符

                2. 必须把前后缀空格去掉

                3. 连续多个空格要合并为一个

代码

class Solution {
public:
    void reverseWords(string &s);
};

void Solution::reverseWords(string &s) {
     int stringSize = s.length();
     if (stringSize == 0) {
         return;
     }
     int begin = 0;
     int end = stringSize-1;
     while (s[begin] == ' ' && (begin < stringSize)){
         ++begin;
     }
     while (s[end] == ' ' && (end >= 0)){
         --end;
     }
     string tmpString = "";
     for (int i = begin; i <= end; ++i) {
         tmpString = tmpString + s[i];
     }
     s = "";
     int tmpStringSize = tmpString.length();
     begin = 0;
     end = tmpStringSize;
     for (int i = tmpStringSize-1; i >= 0; --i) {
         if (tmpString[i] == ' ' || i == 0) {
            if (tmpString[i] == ' ') {
               begin = i;
            }
            else {
               begin = -1;
            }
            for (int j = begin+1; j < end; ++j) {
                s = s + tmpString[j];
            }
            if (begin != -1 && (end-begin > 1)) {
                s = s + ' ';
            }
            end = begin;
      }
}