HammingDistance.js

/*

Hamming distance is a measure of the difference between 
two same-length strings of characters. Simply put, it is 
defined as the number of positions at which corresponding 
characters in two strings of characters are different.

Formally, the Hamming distance between two same-length 
strings of characters, s and t, is defined as the number 
of positions at which the corresponding characters are 
different:

d(s, t) = ∑i |si ≠ ti|

where si and ti are the characters at the i-th position of the 
strings s and t, respectively, and |si ≠ ti| is the indicator 
function that takes the value 1 if si ≠ ti, and 0 otherwise.

The Hamming distance is commonly used in information theory 
and error-correcting codes to measure the amount of errors 
that occur when transmitting data between two points. 

It also has applications in molecular biology for comparing 
sequences of DNA and proteins.

Source: ChatGPT

*/

function hammingDistance(_string1, _string2) {

    if (_string1.length !== _string2.length) {
        return -1;
    }

    let distance = 0;
    
    const L = _string1.length;
    
    for (let i = 0; i < L; i++) {
        
        if (_string1[i] !== _string2[i]) {
            
            distance++;
        }
    }

    return distance;
}

const result = hammingDistance("We're testing the program", "We're testing the machine");

console.log(result);