README_EN.md

2352. Equal Row and Column Pairs

中文文档

Description

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

Solutions

Python3

class Solution:
    def equalPairs(self, grid: List[List[int]]) -> int:
        n = len(grid)
        g = []
        for j in range(n):
            t = []
            for i in range(n):
                t.append(grid[i][j])
            g.append(t)
        return sum(row == col for row in grid for col in g)

Java

class Solution {
    public int equalPairs(int[][] grid) {
        int n = grid.length;
        int[][] g = new int[n][n];
        for (int j = 0; j < n; ++j) {
            for (int i = 0; i < n; ++i) {
                g[i][j] = grid[j][i];
            }
        }
        int ans = 0;
        for (int[] row : grid) {
            for (int[] col : g) {
                boolean ok = true;
                for (int i = 0; i < n; ++i) {
                    if (row[i] != col[i]) {
                        ok = false;
                        break;
                    }
                }
                if (ok) {
                    ++ans;
                }
            }
        }
        return ans;
    }
}

C++

class Solution {
public:
    int equalPairs(vector<vector<int>>& grid) {
        int n = grid.size();
        vector<vector<int>> g(n, vector<int>(n));
        for (int j = 0; j < n; ++j)
            for (int i = 0; i < n; ++i)
                g[i][j] = grid[j][i];
        int ans = 0;
        for (auto row : grid)
            for (auto col : g)
                ans += row == col;
        return ans;
    }
};

Go

func equalPairs(grid [][]int) int {
	n := len(grid)
	g := make([][]int, n)
	for i := range g {
		g[i] = make([]int, n)
	}
	for j := 0; j < n; j++ {
		for i := 0; i < n; i++ {
			g[i][j] = grid[j][i]
		}
	}
	ans := 0
	for _, row := range grid {
		for _, col := range g {
			ok := true
			for i, v := range row {
				if v != col[i] {
					ok = false
					break
				}
			}
			if ok {
				ans++
			}
		}
	}
	return ans
}

TypeScript

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