LeetCode Count and Say

題目

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 nth sequence.

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

 

直接類比

 

代碼：

class Solution {public:string toString(int n)//將數字轉化為string{string ans;int radix=1;while(n/radix>9)radix*=10;while(radix>0){ans.push_back('0'+n/radix);n%=radix;radix/=10;}return ans;}    string countAndSay(int n) {        string ans="1",temp;int i,j,k,len;for(i=1;i<n;i++)//直接類比{len=ans.size();j=0;while(j<len){k=j+1;while(k<len&&ans[k]==ans[j])k++;temp+=toString(k-j);temp.push_back(ans[j]);j=k;}ans=temp;temp.clear();}return ans;    }};