A matrix is Toeplitz if every diagonal from top-left to bottom-right has the same element.
Now given an M x N matrix, return True if and only if the matrix is Toeplitz.
Example 1:
Input: matrix = [[1,2,3,4],[5,1,2,3],[9,5,1,2]]
Output: True
Explanation:
1234
5123
9512
In the above grid, the diagonals are “[9]”, “[5, 5]”, “[1, 1, 1]”, “[2, 2, 2]”, “[3, 3]”, “[4]”, and in each diagonal all elements are the same, so the answer is True.
Example 2:
Input: matrix = [[1,2],[2,2]]
Output: False
Explanation:
The diagonal “[1, 2]” has different elements.
Note:
matrix will be a 2D array of integers.
matrix will have a number of rows and columns in range [1, 20].
matrix[i][j] will be integers in range [0, 99].
题目大意：如果从左上角到右下角的每个对角线具有相同的元素，则矩阵是Toeplitz。给一个矩阵判断它是否是Toeplitz矩阵~
分析：对于每一个元素matrix[i][j]，都判断它是否等于它的右上角元素matrix[i-1][j-1]，如果不相等就返回false，否则循环结束后返回true
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class Solution { public: bool isToeplitzMatrix(vector<vector<int>>& matrix) { for (int i = 1; i < matrix.size(); i++) for (int j = 1; j < matrix[0].size(); j++) if (matrix[i][j] != matrix[i-1][j-1]) return false; return true; } }; |
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