Question

How to shift letters in a string x time by giving an array of shifts in JavaScript

Answer 1

/*

string = “aaa”
After Shifting the first 1 letter by 1 = “baa”
After shifting the first 2 letters by 2 = "dca"
After shifting the first 3 letters 3 = "gfd"
result = "gfd"

*/

function shifLetters(str, shifts) {
    const size = shifts.length;
    let arr = str.split('');
    
    for (let i = size - 1; i >= 0; i--) {
        if (i + 1 < size) {
            shifts[i] += shifts[i + 1];
        }
        
        shifts[i] = shifts[i] % 26;
        let asciicode = str.charAt(i).charCodeAt(0) - 'a'.charCodeAt(0);
        asciicode = asciicode + shifts[i];
        
        if (asciicode > 25) {
            asciicode = asciicode - 26;
        }
        
        arr[i] = String.fromCharCode(('a'.charCodeAt(0) + asciicode));
    }
    
    return arr.join("");
}

let str = "aaa";
const shifts = [1, 2, 3];

str = shifLetters(str, shifts);

console.log(str);



/*
run:
 
gfd
 
*/

 

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