package LeetCode;/**
* @Classname DecodeWays
* @Description 本题和爬楼梯题目是相似的,应该考虑使用递归æ€æƒ³
* @Date 19-2-27 下åˆ3:36
* @Created by mao
*/
public class DecodeWays {
public int numDecodings(String s) {
int result=0;
if(s.length()==0){
return 0;
}
if(s.length()==1){
return 1;
}
if(s.length()==2){
int a=s.charAt(0)-'0';
int b=s.charAt(1)-'0';
int num=a*10+b;
if(num>26){
return 1;
}else {
return 2;
}
}
if(s.length()>2){
for(int i=s.length()-1;i>=2;i--){
int a2=s.charAt(i)-'0';
int b2=s.charAt(i-1)-'0';
int num2=a2+b2*10;
if(num2<=26){
result=numDecodings(s.substring(0,i))+numDecodings(s.substring(0,i-1));
}else{
result=numDecodings(s.substring(0,i));
}
}
}
return result;
}
public static void main(String[] args){
DecodeWays decodeWays=new DecodeWays();
System.out.println(decodeWays.numDecodings("27"));
}
}