[Leetcode] 766. Toeplitz-matrix (simulation) [simple]

link

https://leetcode-cn.com/problems/toeplitz-matrix/

time consuming

Problem solving: 5 min
Problem solving: 6 min

Title

Give you a matrix of mxn. If this matrix is ​​a Toplitz matrix, return true; otherwise, return false.

If the elements on each diagonal from the upper left to the lower right of the matrix are the same, then the matrix is ​​a Toplitz matrix.

prompt:

• m == matrix.length
• n == matrix[i].length
• 1 <= m, n <= 20
• 0 <= matrix[i][j] <= 99

Ideas

According to the definition, check whether all elements are equal to the lower right element. If all elements in the matrix are satisfied, it is the Toplitz matrix.

Time complexity: $O(m\ast n)$

AC code

class Solution {
    
    
public:
    bool isToeplitzMatrix(vector<vector<int>>& matrix) {
    
    
        int m = matrix.size();
        int n = matrix[0].size();
        for(int i = 0; i < m-1; ++i) {
    
    
            for(int j = 0; j < n-1; ++j) {
    
    
                if(matrix[i][j] != matrix[i+1][j+1]) {
    
    
                    return false;
                }
            }
        }
        return true;
    }
};