Cross-Stitch Pattern

Easy

An embroiderer stores a design as a square table pattern of size n × n: each cell holds a thread number, and 0 means the cell is empty. The design is a **cross** when: - neither diagonal (top-left to bottom-right, and top-right to bottom-left) has an empty cell; - every cell off the diagonals is empty. Return True if pattern is a cross, and False otherwise.

Example 1

pattern=[[4, 0, 7], [0, 9, 0], [1, 0, 3]] → True

Both diagonals are filled (4, 9, 3 and 7, 9, 1) and every other cell is zero, so it is a cross.

Example 2

pattern=[[2, 0, 0, 5], [0, 1, 6, 0], [0, 8, 0, 0], [3, 0, 0, 4]] → False

The cell on the main diagonal in the third row is 0, so a stitch is missing.

Example 3

pattern=[[1, 0, 1], [0, 1, 0], [1, 2, 1]] → False

The diagonals are filled, but there is a stray stitch (2) in the middle of the bottom row.

Constraints

3 ≤ n ≤ 100
pattern is a square n × n table
0 ≤ pattern[i][j] ≤ 10⁵

Have you seen this problem in a real interview?

Solved by0

Tried by0

Submissions0

Acceptance—

Topics

Array Matrix

Similar problems

Crossword That Reads Both Ways Easy Island Coastline Length Easy Repack the Tray Easy Blur the Pixels Easy Paint Bucket Tool Easy

Input

pattern=[[4, 0, 7], [0, 9, 0], [1, 0, 3]]

Expected

True

Run checks the first 3 tests in your browser. Submit checks all 73 tests on the server, hidden ones included.