LeetCode in Kotlin

821. Shortest Distance to a Character

Easy

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.

Example 1:

Input: s = “loveleetcode”, c = “e”

Output: [3,2,1,0,1,0,0,1,2,2,1,0]

Explanation: The character ‘e’ appears at indices 3, 5, 6, and 11 (0-indexed).

The closest occurrence of ‘e’ for index 0 is at index 3, so the distance is abs(0 - 3) = 3.

The closest occurrence of ‘e’ for index 1 is at index 3, so the distance is abs(1 - 3) = 2.

For index 4, there is a tie between the ‘e’ at index 3 and the ‘e’ at index 5, but the distance is still the same: abs(4 - 3) == abs(4 - 5) = 1.

The closest occurrence of ‘e’ for index 8 is at index 6, so the distance is abs(8 - 6) = 2.

Example 2:

Input: s = “aaab”, c = “b”

Output: [3,2,1,0]

Constraints:

Solution

class Solution {
    fun shortestToChar(s: String, c: Char): IntArray {
        val result = IntArray(s.length)
        result.fill(Int.MAX_VALUE)
        for (i in s.indices) {
            if (s[i] == c) {
                result[i] = 0
            }
        }
        for (i in s.indices) {
            if (result[i] != 0) {
                var j = i - 1
                while (j >= 0 && result[j] != 0) {
                    j--
                }
                if (j >= 0) {
                    result[i] = i - j
                }
                j = i + 1
                while (j < s.length && result[j] != 0) {
                    j++
                }
                if (j < s.length) {
                    result[i] = result[i].coerceAtMost(j - i)
                }
            }
        }
        return result
    }
}