DP

by Krishna Ananthi

JavaScript

function  numDecodings(s) {
        let dp = new Array(s.length + 1).fill(0);
        dp[s.length] = 1;
        for (let i = s.length - 1; i >= 0; i--) {
        console.log('**',dp)
            if (s.charAt(i) === '0') {
                dp[i] = 0;
            } else {
                dp[i] = dp[i + 1];
                if (i + 1 < s.length && (s.charAt(i) === '1' ||
                   (s.charAt(i) === '2' && s.charAt(i + 1) < '7'))) {
                   dp[i] += dp[i + 2];
                }
            }
        console.log(dp)
        }
        return dp[0];
    }
    
    console.log(numDecodings("1120"))