How should I practice Number of Islands?

Start by reading the full statement, solve the visible examples, then compare the pattern against related CrowdStrike onsite interview problems in FastPrep.

Is Number of Islands associated with CrowdStrike?

FastPrep tags this as a CrowdStrike onsite interview coding practice problem when the problem catalog has that company and stage context.

Problem · Matrix

Number of Islands

Learn this problem

● Medium

CrowdStrikeFULLTIMEONSITE INTERVIEW

Problem statement

Given an array of equal-length strings grid, where '1' represents land and '0' represents water, return the number of islands.

An island is a maximal group of land cells connected horizontally or vertically. Cells outside the matrix are water.

Function

countIslands(grid: String[]) → int

Examples

Example 1

grid = ["11110","11010","11000","00000"]return = 1

All land cells belong to one orthogonally connected component.

Example 2

grid = ["11000","11000","00100","00011"]return = 3

The upper-left block, center cell, and lower-right pair are separate islands.

Constraints

1 <= grid.length <= 300.
1 <= grid[i].length <= 300 and every row has the same length.
Every character is '0' or '1'.