Toeplitz Matrix

Difficulty: 1100 2000 ms 128 MB

implementation

Is the matrix Toeplitz — constant along every top-left-to-bottom-right diagonal?

Input: the first line has N and M; the next N lines each have M integers.

Output: YES or NO.

Constraints:

• 1 ≤ N, M ≤ 100

Sample Tests

3 4
1 2 3 4
5 1 2 3
9 5 1 2

YES

2 2
1 2
2 2

NO

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