#791 - Custom Sort String

Medium • View on LeetCode • View on GitHub

Problem Description

S and T are strings composed of lowercase letters. In S, no letter occurs more than once.

S was sorted in some custom order previously. We want to permute the characters of T so that they match the order that S was sorted. More specifically, if x occurs before y in S, then x should occur before y in the returned string.

Return any permutation of T (as a string) that satisfies this property.

Solution

/**
 * @param {string} S
 * @param {string} T
 * @return {string}
 */
var customSortString = function(S, T) {
  const order = S.split('').reduce((o, k, i) => ({...o, [k]: i}), {});
  return T.split('').sort((a, b) => (order[a] || 0) - (order[b] || 0)).join('');
};