题目：

题解：

class Solution {
public:string countAndSay(int n) {string prev = "1";for (int i = 2; i <= n; ++i) {string curr = "";int start = 0;int pos = 0;while (pos < prev.size()) {while (pos < prev.size() && prev[pos] == prev[start]) {pos++;}curr += to_string(pos - start) + prev[start];start = pos;}prev = curr;}return prev;}
};