leetcode Count and Say

题目连接

https://leetcode.com/problems/count-and-say/ 

Count and Say

Description

The count-and-say sequence is the sequence of integers beginning as follows:
1, 11, 21, 1211, 111221, ...

1 is read off as "one 1" or 11.
11 is read off as "two 1s" or 21.
21 is read off as "one 2, then one 1" or 1211.
Given an integer n, generate the $n^{th}$ sequence.

Note: The sequence of integers will be represented as a string.

直接模拟。。

class Solution {
public:
	string countAndSay(int n) {
		char ch;
		int m, tot = 0;
		string ans = "1";
		while (--n) {
			string ret = "";
			m = ans.length();
			for (int j = 0; j < m;) {
				tot = 0;
				ch = ans[j];
				for (; ch == ans[j]; j++) tot++;
				ret += to_string(tot) + ch;
			}
			ans = ret;
		}
		return ans;
	}
};