How should I practice Validate a Nonogram?

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

Is Validate a Nonogram 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 a Nonogram

WhatNot● MediumINTERNPHONE SCREEN

Learn

Problem statement

A nonogram clue lists the lengths of the consecutive filled runs in one row or column. A filled cell is 1 and an empty cell is 0.

Given a rectangular binary matrix grid, one clue list per row in rowClues, and one clue list per column in colClues, return true exactly when every clue matches the matrix.

Read each row from left to right and each column from top to bottom.
Each clue value describes one maximal consecutive run of 1 cells. Separate runs have at least one 0 between them.
Run lengths must match in order, not just in total.
An empty clue list means that the line contains no 1 cells.
Validate the supplied matrix; do not solve the puzzle or change its cells.

Function

validateNonogram(grid: int[][], rowClues: int[][], colClues: int[][]) → boolean

Examples

Example 1

grid = [[1,1,0],[0,1,0],[1,1,1]]rowClues = [[2],[1],[3]]colClues = [[1,1],[3],[1]]return = true

The row runs are [2], [1], and [3]. Reading columns top to bottom gives [1,1], [3], and [1].

Example 2

grid = [[1,1,0],[0,1,0],[1,1,1]]rowClues = [[2],[1],[3]]colClues = [[2],[3],[1]]return = false

The first column contains two separate runs of length 1, so the clue [2] is incorrect even though both contain two filled cells.

Example 3

grid = [[0,0],[0,0]]rowClues = [[],[]]colClues = [[],[]]return = true

Every row and column is empty of filled cells, so each clue is an empty list.

Constraints

1 <= grid.length <= 20 and all rows have the same length c, with 1 <= c <= 20.
Each grid value is 0 or 1.
rowClues.length == grid.length and colClues.length == c.
A row clue list contains at most c values, each from 1 to c.
A column clue list contains at most grid.length values, each from 1 to grid.length.
Clues may be inconsistent with the grid or impossible to fit; return false in either case.