Question

How to decrypt string from a string containing digits (0-9) and # by using numbers mapping in Java

Answer 1

// numbers mapping:
 
// a = 1
// b = 2
// ...
// j = 10#
// ...
// z = 26#


class Program {
    private static char ConvertToLowercaseCharachter(String str) {
	    int num = Integer.parseInt(str);
        
        return (char)(num + 96);
    }
    
    private static String DecryptString(String str) {
        StringBuilder sb = new StringBuilder();
        int i = 0;
        
        while (i < str.length() - 2) {
            char ch;
            if (str.charAt(i + 2) == '#') {
                ch = ConvertToLowercaseCharachter(str.substring(i, i + 2));
                i+=2;
            } else {
                ch = ConvertToLowercaseCharachter(str.substring(i, i + 1));
            }
            i++;
            sb.append(ch);
        }
        
        while (i < str.length()) {
            char ch = ConvertToLowercaseCharachter(str.substring(i, i + 1));
            sb.append(ch);
            i++;
        }
        
        return sb.toString();
    }
    
    public static void main(String[] args) 
    {
        System.out.print(DecryptString("12310#11#26#"));
    } 
}




/*
run:
 
abcjkz
 
*/

 

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