- Difficulty: Medium
- Tags: LeetCode, Medium, Array, Hash Table, Matrix, Simulation, leetcode-2352, O(n^2)
Problem
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] <= 105