【Leetcode】Count and Say

题目链接：https://leetcode.com/problems/count-and-say/

题目：

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.

思路：

题目看懂了就好做了。。

算法：

public String countAndSay(int n) {
String r = "1";
for (int i = 1; i < n; i++) {
String t = "";
int count = 0;
String flag = r.charAt(0) + "";
for (int j = 0; j < r.length(); j++) {
if ((r.charAt(j) + "").equals(flag)) {
count++;
} else {
t += count + "" + flag;
flag = r.charAt(j) + "";
count = 1;
}
}
t += count + "" + flag;
r = t;
}
return r;
}