leetcode 38

38. Count and Say

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.

说真的刚开始真不知道这道题要干什么，英语有点差~~~

当明白是什么意思的时候又发现描述起来有点问题，语文有点差~~~

生硬的描述一下吧：1被读作“1个1” 或  11；11被读作“2个1”或21；21被读作“1个2,1个1”或1211；依次这样下去，输出第n个序列。

代码如下：

 1 class Solution {
 2 public:
 3     string countAndSay(int n) {
 4         string first = "1";
 5         for(int i = 1; i < n; i++)
 6         {
 7            string ss = "";
 8            int count = 1;
 9            for(int j = 1; j < first.length(); j++)
10            {
11                if(first[j-1] == first[j])
12                {
13                    count ++;
14                }
15                else
16                {
17                    ss = ss + (char)(count + ‘0‘) + first[j-1];
18                    count = 1;
19                }
20            }
21            first = ss + (char)(count + ‘0‘) + first[first.length()-1];
22         }
23         return first;
24     }
25 };