Code snipet

class Solution:
    def maxDistance(self, s: str, k: int) -> int:
        ans = 0
        north = south = east = west = 0

        for i, c in enumerate(s):
            if c == 'N':
                north += 1
            elif c == 'S':
                south += 1
            elif c == 'E':
                east += 1
            elif c == 'W':
                west += 1

            vertical = abs(north - south)
            horizontal = abs(east - west)
            MD = vertical + horizontal
            # Max possible distance at this step using up to k changes
            max_possible = MD + min(2 * k, i + 1 - MD)
            ans = max(ans, max_possible)

        return ans