LeetCode 之 Count and Say

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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.

这个题的描述有点迷惑性，而且这还是有过更正的，我看discuss上有人讨论说之前更误导人。只看前五个例子，还是有可能理解错，正确的第6的sequence：312211。现在我们理解这个题的意思了，“个数”+“数字”组合起来，实现上从低到高迭代生成就行了。

<span style="color:#333333;">class Solution {public:    string countAndSay(int n) {        string ans="1";        if(n==1) return ans;        //string ans=last;        for(int i=2;i<=n;i++){            string temp;            int m=0,n=0;            while(n!=ans.size()){                if(ans[n]==ans[m]&&n==(ans.size()-1)){</span><span style="color:#cc0000;">temp+=std::to_string(n-m+1)+ans[m]</span><span style="color:#333333;">;n++;}                else if(ans[n]==ans[m]&&n!=(ans.size()-1)){                    n++;                }else{                    </span><span style="color:#ff0000;">temp+=std::to_string(n-m)+ans[m];</span><span style="color:#333333;">                    m=n;                }            }            ans=temp;        }        return ans;    }};</span>

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