Leetcodes Solution 38 Count and Say

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The count-and-say sequence is the sequence of integers with the first five terms as following:

1. 12. 113. 214. 12115. 111221

1 is read off as "one 1" or 11.

11 is read off as "two 1s" or 21.

Given an integer n, generate the nth term of the count-and-say sequence.

Note: Each term of the sequence of integers will be represented as a string.

Example 1:

Input: 1Output: "1"

Example 2:

Input: 4Output: "1211"

思路1

直接根據輸入的n對數列數n次

class Solution{public: string countAndSay(int n){ if(n == 0) return ""; string res = "1"; while(--n){ string cur = ""; for(int i = 0; i < res.size(); i++){ int count = 1; while((i + 1 < res.size()) && (res[i] == res[i+1])){ count++; i++; } cur += to_string(count) + res[i]; } res = cur; } return res; }};

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