一、题目内容

image.png

二、题解

解法1：

思路

转移方程
后两位可单独翻译，则
dp[i] = dp[i-1] + dp[i-2]
否则
dp[i] = dp[i-1]

image.png

代码

  1. public class Solution {
  3.     public int translateNum(int num) {
  4.         String str = String.valueOf(num);
  5.         int[] dp = new int[str.length() + 1];
  6.         dp[0] = 1;
  7.         dp[1] = 1;
  9.         for (int i = 2; i <= str.length(); i++) {
  10.             String temp = str.substring(i - 2, i);
  11.             dp[i] = temp.compareTo("10") >= 0 && temp.compareTo("25") <= 0 ? dp[i - 1] + dp[i - 2] : dp[i - 1];
  12.         }
  13.         return dp[str.length()];
  14.     }
  15. }
public class Solution {

    public int translateNum(int num) {
        String s = String.valueOf(num);

        int a = 1, b = 1;
        for (int i = 2; i <= s.length(); i++) {
            String tmp = s.substring(i - 2, i);
            int c = tmp.compareTo("10") >= 0 && tmp.compareTo("25") <= 0 ? a + b : a;
            b = a;
            a = c;
        }
        return a;
    }
}