关关的刷题日记47Leetcode 38. Count and Say

Posted 2021-07-16 专知

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关关的刷题日记47 – Leetcode 38. Count and Say

题目

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

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 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: 1 Output: "1" Example 2:

Input: 4 Output: "1211"

题目的意思：将由数字构成的字符串读出来成为一个新的字符串。比如1口语是1个1，记作11；11读作2个1，记作21；21读作1个2，1个1，记作1211……。输入n，计算第n个这样的数字。

思路

思路：按照将字符串读出来成为一个新的字符串的思路来暴力求解。

class Solution {
public:
    string countAndSay(int n) {
        if(n==0)
            return "";
        if(n==1)
            return "1";
        string s="1";
        for(int i=1; i<n; i++)
        {
            int count=1;
            string temp="";
            for(int i=0; i< s.size()-1; i++)
            {
                if(s[i+1]==s[i])
                    ++count;
                else
                {
                    temp=temp+char(count+'0')+s[i];
                    count=1;
                }  
            }
            s=temp+char(count+'0')+s[s.size()-1];
        }
        return s;
    }
};