BinarySearch 0767 Closest Distance to Character

Problem statement

https://binarysearch.com/problems/Closest-Distance-to-Character/

Solution

Equal to Leetcode 0821. Shortest Distance to a Character.

Complexity

Time and space is O(n).

Code

class Solution:
    def solve(self, S, C):
        def letter_get(letter, dr):
            n = len(S)
            res, cur = [0]*n, -n
            for i in range(n)[::dr]:
                if S[i] == letter: cur = i
                res[i] = abs(i - cur)
            return res
        
        return [min(x,y) for x,y in zip(letter_get(C, 1), letter_get(C, -1))]