Leetcode count and say

The count-and-say sequence is the sequence of integers beginning as follows:
1, 11, 21, 1211, 111221, ...

1Is read off"one 1"Or11.
11Is read off"two 1s"Or21.
21Is read off"one 2, Thenone 1"Or1211.

Given an integerN, GenerateNTh sequence.

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

 

 1 public class Solution { 2     String lastString; 3     public String countAndSay(int n) { 4         if (n==0) { 5             return lastString; 6         } 7         lastString="1"; 8         if (n==1) { 9             return lastString;10         }11         12         for (int i = 2; i <=n ; i++) {13             int count=0;14             String currsString="";15             for (int j = 0; j < lastString.length(); j++) {16                 if (j==0||lastString.charAt(j)==lastString.charAt(j-1)) {17                     ++count;18                 }else {19                     currsString=currsString+count+lastString.charAt(j-1);20                     count=1;21                 }22             }23             currsString=currsString+count+lastString.charAt(lastString.length()-1);24             lastString=currsString;25         }26         return lastString;27     }28 }

 

Leetcode count and say