2133. Check if Every Row and Column Contains All Numbers

 An n x n matrix is valid if every row and every column contains all the integers from 1 to n (inclusive).

Given an n x n integer matrix matrix, return true if the matrix is valid. Otherwise, return false.

 

Example 1:

Input: matrix = [[1,2,3],[3,1,2],[2,3,1]]
Output: true
Explanation: In this case, n = 3, and every row and column contains the numbers 1, 2, and 3.
Hence, we return true.

Example 2:

Input: matrix = [[1,1,1],[1,2,3],[1,2,3]]
Output: false
Explanation: In this case, n = 3, but the first row and the first column do not contain the numbers 2 or 3.
Hence, we return false.

 

Constraints:

• n == matrix.length == matrix[i].length
• 1 <= n <= 100
• 1 <= matrix[i][j] <= n

創造2*n的集合 來儲存行跟列

如果已經發生 return False

否則+進去集合裡面

就這樣

class Solution:
    def checkValid(self, matrix: List[List[int]]) -> bool:
        n=len(matrix)
        
        L=[set() for i in range(2*n)]
        
        for i in range(n):
            for j in range(n):
                if matrix[i][j] in L[i] or matrix[i][j] in L[j+n]:
                    return False
                else:
                    L[i].add(matrix[i][j])
                    L[j+n].add(matrix[i][j])
               
        
        return True