How should I practice Count Connected Islands?

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

Is Count Connected Islands associated with Uber?

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

Count Connected Islands

Uber● MediumFULLTIMEPHONE SCREEN

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Problem statement

You are given a rectangular binary matrix grid. A cell containing 1 is land and a cell containing 0 is water. Land cells belong to the same island when they are connected horizontally or vertically.

Return the number of islands.

Function

numberOfIslands(grid: int[][]) → int

Examples

Example 1

grid = [[1,1,1,1,0],[1,1,0,1,0],[1,1,0,0,0],[0,0,0,0,0]]return = 1

All land cells are connected through horizontal or vertical moves.

Example 2

grid = [[1,1,0,0,0],[1,1,0,0,0],[0,0,1,0,0],[0,0,0,1,1]]return = 3

The top-left block, center cell, and bottom-right pair are separate islands.

Example 3

grid = [[0,0],[0,0]]return = 0

No cell is land.

Constraints

1 <= grid.length <= 300.
1 <= grid[i].length <= 300.
Every row has the same length.
Every value is 0 or 1.