"""
Given a 0-indexed n x n integer matrix grid, return the number of pairs (Ri, Cj) such that row Ri and column Cj are equal.

A row and column pair is considered equal if they contain the same elements in the same order (i.e. an equal array).



Example 1:
Input: grid = [[3,2,1],[1,7,6],[2,7,7]]
Output: 1
Explanation: There is 1 equal row and column pair:
- (Row 2, Column 1): [2,7,7]

Example 2:
Input: grid = [[3,1,2,2],[1,4,4,5],[2,4,2,2],[2,4,2,2]]
Output: 3
Explanation: There are 3 equal row and column pairs:
- (Row 0, Column 0): [3,1,2,2]
- (Row 2, Column 2): [2,4,2,2]
- (Row 3, Column 2): [2,4,2,2]

Constraints:
n == grid.length == grid[i].length
1 <= n <= 200
1 <= grid[i][j] <= 10^5
"""
import collections
from typing import List


class Solution:
    def equalPairs(self, grid: List[List[int]]) -> int:
        cnt = collections.defaultdict(int)
        res = 0
        for row in grid:
            cnt[tuple(row)] += 1
        transpose = [*zip(*grid)]
        for col in transpose:
            res += cnt[col]
        return res
