Question

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

Answer 1

/*
numbers mapping:

a = 1
b = 2
...
j = 10#
...
z = 26#
*/

function decryptString(str: string) {
    let result: string = "";
    let i: number = 0;
    
    while (i < str.length) {
        if (i + 2 < str.length && str[i + 2] === '#') {
            let num = (parseInt(str[i], 10) * 10) + parseInt(str[i + 1], 10);
            result += String.fromCharCode(num + 96);
            i += 3;
        } else {
            result += String.fromCharCode(parseInt(str[i], 10) + 96);
            i += 1;
        }
    }

    return result;
}

let decrypted: string = decryptString("12310#11#26#");

console.log(decrypted);




/*
run:

"abcjkz" 

*/

 

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