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.
1 public class Solution { 2 public String countAndSay(int n) { 3 String result = "1"; 4 5 for(int i = 1; i < n; i++){ 6 char array_char[] = result.toCharArray(); 7 int count = 1;//record count 8 result = new String();//暂存 9 for(int j = 0; j < array_char.length; ){//start read 10 int k = j + 1; 11 12 while(k < array_char.length && array_char[k] == array_char[j]) 13 { 14 count++; 15 k++; 16 }//equal count ++ 17 18 result += String.valueOf(count); 19 result += array_char[j]; 20 j = k; 21 count = 1; 22 23 } 24 } 25 26 return result; 27 } 28 }
按照定义来做