Count and Say

参考：http://blog.csdn.net/linhuanmars/article/details/20679963

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.

实际在跑的时候，内层的循环当进行到最后一次的时候，只会计数而不会往res上添加结果，所以要在内层循环外再补上。

代码：

package leetcode;public class CountAndSay {public static void main(String args[]){System.out.println(new CountAndSay().countAndSay(4));}public String countAndSay(int n) {if (n < 0)return "";String curRes = "1";for (int i = 2; i <= n; i++) {int count = 1;String res = "";for (int j = 1; j < curRes.length(); j++) {if (curRes.charAt(j - 1) == curRes.charAt(j)) {count++;} else {res += count;res += curRes.charAt(j - 1);count = 1;}}//举个例子就懂了.. res += count;        res += curRes.charAt(curRes.length()-1);         curRes = res;}return curRes;}}