剑指Offer - 面试题58 - II. 左旋转字符串

示例 1：
输入: s = "abcdefg", k = 2
输出: "cdefgab"

示例 2：
输入: s = "lrloseumgh", k = 6
输出: "umghlrlose"
 
限制：
1 <= k < s.length <= 10000

class Solution {
public:
    string reverseLeftWords(string s, int n) {
        if(n == s.size())
        	return s;
        int i = 0, count = n, size = s.size();
        while(count--)
        	s.push_back(s[i++]);
        return s.substr(n,size);
    }
};

class Solution {
public:
    string reverseLeftWords(string s, int n) {
        return s.substr(n,s.size()-n)+s.substr(0,n);
    }
};