[LeetCode]Decode Ways

[LeetCode]Decode Ways

A message containing letters from A-Z is being encoded to numbers using the following mapping:

'A' -> 1
'B' -> 2
...
'Z' -> 26

Given an encoded message containing digits, determine the total number of ways to decode it.

For example,
Given encoded message "12", it could be decoded as "AB" (1 2) or "L" (12).

The number of ways decoding "12" is 2.

迭代較簡單，遞歸超時

public class Solution {
	public int numDecodings(String s) {
		int len = s.length();
		if(len == 0) return 0;
		int prev = 1;
		int cur = s.charAt(0)>'0'?1:0;
		if(cur == 0) return 0;
		for(int i=1;i26) {
				prev = temp;
				continue;
			}
			cur += prev;
			prev = temp;
		}
		return cur;
	}
}