#字符串 #替换空格

ti-huan-kong-ge-lcof.cpp

class Solution {
public:
    string replaceSpace(string s) {
        int space_cnt = count(s.begin(), s.end(), ' ');
        if (space_cnt < 0) return s;

        int lft = s.size() - 1;
        int rht = s.size() + space_cnt * 2 - 1;
        s.resize(s.size() + space_cnt * 2);
        for (; lft >= 0; lft--) {
            if (s[lft] != ' ') {
                s[rht] = s[lft];
                rht--;
            } else {
                s[rht] = '0';
                s[rht-1] = '2';
                s[rht-2] = '%';
                rht -= 3;
            }
        }
        return s;
    }
};