题解 | #字符串变形#

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param s string字符串 
     * @param n int整型 
     * @return string字符串
     */
    string trans(string s, int n) {
        // write code here
        int start = 0;
        int end = 0;
        string res = "";
        for(int i = 0; i < n; i++)
        {
            if(s[i] >= 'A' && s[i] <= 'Z'){
                s[i] += 32;
            }else if((s[i] >= 'a' && s[i] <= 'z')){
                s[i] -= 32;
            }else if (s[i] == ' '){
                end = i;
                res = " " + s.substr(start,end-start) + res;
                start = end + 1;
            }
        }
        string end_str = s.substr(start,n-end);
        res = end_str + res;
        return res;
    }
};