Code RoomNumber of distinct islands
HardPrep Room Coding #1481

Number of distinct islands

CodingAlgorithms & data structuresSenior–Staff~35 min

Given an m x n binary grid, an island is a group of 1s connected 4-directionally. Two islands are considered the same if and only if one can be translated (shifted, not rotated or reflected) to equal the other. Return the number of distinct island shapes. The grid may be empty of land.

Implement
num_distinct_islands(grid: list[list[int]]) → int
Examples
in[[[1,1,0,0,0],[1,1,0,0,0],[0,0,0,1,1],[0,0,0,1,1]]]out1
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

0:00 of about 35 min
InputExpectedGot
[[[1,1,0,0,0],[1,1,0,0,0],[0,0,0,1,1],[0,0,0,1,1]]]1not run yetsample