#821 - Shortest Distance to a Character

Easy • View on LeetCode • View on GitHub

Problem Description

Given a string s and a character c that occurs in s, return an array of integers answer where answer.length == s.length and answer[i] is the distance from index i to the closest occurrence of character c in s.

The distance between two indices i and j is abs(i - j), where abs is the absolute value function.

Solution

/**
 * @param {string} s
 * @param {character} c
 * @return {number[]}
 */
var shortestToChar = function(s, c) {
  const result = [];
  const pointers = [];

  for (let i = 0; i < s.length; i++) {
    if (s[i] === c) pointers.push(i);
  }

  for (let i = 0, j = 0; i < s.length; i++) {
    if (i > pointers[j + 1] && pointers.length - 2 > j) {
      j++;
    }

    const offset = pointers.length > 1
      ? Math.min(Math.abs(pointers[j] - i), Math.abs(pointers[j + 1] - i))
      : Math.abs(pointers[j] - i);

    result.push(offset);
  }

  return result;
};