freecodecamp--freecodecamp/curriculum/challenges/english/blocks/daily-coding-challenges-javascript/6a22d77ddf034bc4e35b1d57.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
6a22d77ddf034bc4e35b1d57	Challenge 350: Letter Distance	28	challenge-350

--description--

Given two strings of equal length, return the sum of the shortest distances between each pair of characters.

• The input will only contain lowercase letters
• The alphabet is treated as a circle, so the distance between a and z is 1.

--hints--

letterDistance("abc", "bcd") should return 3.

assert.equal(letterDistance("abc", "bcd"), 3);

letterDistance("abc", "xyz") should return 9.

assert.equal(letterDistance("abc", "xyz"), 9);

letterDistance("encrypt", "decrypt") should return 10.

assert.equal(letterDistance("encrypt", "decrypt"), 10);

letterDistance("algorithm", "codeblock") should return 43.

assert.equal(letterDistance("algorithm", "codeblock"), 43);

letterDistance("lobster", "penguin") should return 47.

assert.equal(letterDistance("lobster", "penguin"), 47);

letterDistance("alligator", "crocodile") should return 55.

assert.equal(letterDistance("alligator", "crocodile"), 55);

--seed--

--seed-contents--

function letterDistance(str1, str2) {

  return str1;
}

--solutions--

function letterDistance(str1, str2) {
  return str1.split("").reduce((sum, char, i) => {
    const diff = Math.abs(char.charCodeAt(0) - str2[i].charCodeAt(0));
    return sum + Math.min(diff, 26 - diff);
  }, 0);
}