How should I practice Validate Rows and Columns?

Start by reading the full statement, solve the visible examples, then compare the pattern against related WhatNot phone screen problems in FastPrep.

Is Validate Rows and Columns associated with WhatNot?

FastPrep tags this as a WhatNot phone screen coding practice problem when the problem catalog has that company and stage context.

Validate Rows and Columns

WhatNot● EasyNEW GRADPHONE SCREEN

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Problem statement

You are given a nonempty square integer matrix grid with n rows and n columns. Return true if every row and every column is valid; otherwise return false.

For this exercise, a valid row or column contains every integer from 1 through n exactly once. A value outside that range makes the grid invalid.

The grid is fully filled. Check rows and columns only; there is no subgrid or diagonal requirement.

Function

isValidGrid(grid: int[][]) → boolean

Examples

Example 1

grid = [[1,2],[2,1]]return = true

Every row and column contains 1 and 2 exactly once.

Example 2

grid = [[1,2],[1,2]]return = false

The rows are valid, but each column repeats a value.

Example 3

grid = [[0]]return = false

A one-cell grid must contain 1; 0 is outside its allowed range.

Constraints

For this exercise, assume 1 <= n <= 50.
grid.length == n and grid[i].length == n.
For this exercise, assume -10^9 <= grid[i][j] <= 10^9.