题解 | #把数字翻译成字符串#

import java.util.*;


public class Solution {
    /**
     * 解码
     * @param nums string字符串 数字串
     * @return int整型
     */
    public int solve (String nums) {
        // write code here
        char[] ch = nums.toCharArray();
        int n = ch.length;
        int[] dp = new int[n+1];
        dp[n] = 1;
        for(int i = n-1;i>=0;i--){
            if(ch[i] == '0'){
                dp[i] = 0;
            }else if(ch[i] == '1'){
                int ans = dp[i+1];
                if(i+1<ch.length){
                    ans += dp[i+2];
                }
                dp[i] = ans;
            }else if(ch[i] == '2'){
                int ans = dp[i+1];
                if(i+1<ch.length&&ch[i+1]<'7'){
                    ans += dp[i+2];
                }
                dp[i] = ans;
            }else{
                dp[i] = dp[i+1];
            }
    
        }
        return dp[0];
    
    }  
    
}