Count and Say

注意 char+int 得到的还是int值 直接加到结果字符串上面
可以使用：sBuilder.append(Integer.toString(count)+lastChar);
sBuilder.append(""+count+lastChar);
避免问题
//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.
public class CountandSay {


public static void main(String[] args) {
// TODO 自动生成的方法存根
System.out.print(countAndSay(2));
}
public static String countAndSay(int n) {
String input="1";
for(int i=1;i<n;i++){
input=countAndSayForOneString(input);
}
return input;
}
private  static String countAndSayForOneString(String input) {
// TODO 自动生成的方法存根
char lastChar=input.charAt(0);
int count=1;
StringBuilder sBuilder=new StringBuilder();
for(int i=1;i<input.length();i++){
if(input.charAt(i)==lastChar){
count++;
}else {
sBuilder.append(Integer.toString(count)+lastChar);
count=1;
lastChar=input.charAt(i);
}
}
sBuilder.append(""+count+lastChar);
return sBuilder.toString();
}
}