2857. Count Pairs of Points With Distance k

Tags:

• Medium
• bits
• practice

Link

a^b = x , a = x^b

dateset = 50000 and 100 , find the solution from data range

split k into a and b

then for each node x1, y1 , find the corresponding x2 , y2

class Solution:
    def countPairs(self, coordinates: List[List[int]], k: int) -> int:

        res = 0

        for i in range(k+1):
            M = defaultdict(int)

            for x1, y1 in coordinates:
                x2 = i ^ x1
                y2 = (k-i) ^ y1

                res += M[(x2,y2)]

                M[(x1,y1)] += 1

        return res