1779. Find Nearest Point That Has the Same X or Y Coordinate

class Solution:
    def nearestValidPoint(self, x: int, y: int, points: List[List[int]]) -> int:
        """
        1. find valid points (share same x or y ) 
        2. within valid points, smallest distance 
        3. res to record smallest index when first appear  
         tc O(N) sc O(1)
        """
        min_d = float('inf')
        res = -1 
        for idx, (i,j) in enumerate(points):
            #dx,dy = x-i,y-j 
            if i == x or j == y: #  if  dx*dy == 0  and abs(dx+dy) < min_d 
                d = abs(i-x) + abs(j-y) 
                if min_d > d:
                    res = idx
                    min_d = d 
                
        return res