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.
双指针，记录相同的出现的字符的个数 ；
1 public class Solution { 2 public String countAndSay(int n) { 3 4 String say = "1"; 5 for(int i = 1; i < n ; i++){ 6 say = build(say); 7 } 8 return say; 9 } 10 11 public String build(String s){ 12 int len = s.length(); 13 int last = 0; 14 String temp = ""; 15 for(int i = 0; i < len; i++){ 16 if(s.charAt(last) != s.charAt(i)){ 17 temp = temp + (i-last)+s.charAt(last); 18 last = i; 19 } 20 } 21 22 if(last < len){ 23 temp = temp + (len -last) + s.charAt(last); 24 } 25 26 return temp; 27 } 28 }
原文：http://www.cnblogs.com/RazerLu/p/3545735.html