How should I practice Report Island Areas in Discovery Order?

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

Is Report Island Areas in Discovery Order associated with Snap Inc.?

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Problem · Array

Report Island Areas in Discovery Order

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Snap Inc.FULLTIMEPHONE SCREEN

Problem statement

Given a rectangular binary matrix grid, return the area of every island.

An island is a maximal group of cells containing 1 connected horizontally or vertically. Its area is its number of cells.

Scan cells in row-major order, from top to bottom and left to right. When an unvisited land cell starts a new island, append that island's area to the result. Return an empty array when the grid contains no land.

Function

islandAreas(grid: int[][]) → int[]

Examples

Example 1

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

The scan first reaches the three-cell island in the upper-left, then the three-cell island in the lower-right.

Example 2

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

The two one-cell islands are discovered before the three-cell island in the bottom row.

Example 3

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

The grid contains no land, so there are no island areas to report.

Constraints

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