Skip to content

Prepare For Coder Interview – Denny

  • Basic
  • Medium
  • Hard
  • Architect
  • Life

LeetCode: Number of Distinct Islands II

Posted on May 14, 2018July 26, 2020 by braindenny

Number of Distinct Islands II



Similar Problems:

  • Series: Island & Follow-up
  • Number of Distinct Islands
  • CheatSheet: Leetcode For Code Interview
  • CheatSheet: Common Code Problems & Follow-ups
  • Tag: #dfs, #classic, #rotatelist, #island

Given a non-empty 2D array grid of 0’s and 1’s, an island is a group of 1’s (representing land) connected 4-directionally (horizontal or vertical.) You may assume all four edges of the grid are surrounded by water.

Count the number of distinct islands. An island is considered to be the same as another if they have the same shape, or have the same shape after rotation (90, 180, or 270 degrees only) or reflection (left/right direction or up/down direction).

Example 1:

11000
10000
00001
00011

Given the above grid map, return 1.

Notice that:

11
1

and

 1
11

are considered same island shapes. Because if we make a 180 degrees clockwise rotation on the first island, then two islands will have the same shapes.

Example 2:

11100
10001
01001
01110

Given the above grid map, return 2.

Here are the two distinct islands:

111
1

and

1
1

Notice that:

111
1

and

1
111

are considered same island shapes. Because if we flip the first array in the up/down direction, then they have the same shapes.

Note: The length of each dimension in the given grid does not exceed 50.

Github: code.dennyzhang.com

Credits To: leetcode.com

Leave me comments, if you have better ways to solve.


// https://code.dennyzhang.com/number-of-distinct-islands-ii

linkedin
github
slack

Post Views: 11
Posted in HardTagged #classic, #dfs, island, rotatelist

Post navigation

LeetCode: Design Tic-Tac-Toe
LeetCode: The Maze

Leave a Reply Cancel reply

Your email address will not be published.

Tags

#array #backtracking #bfs #binarytree #bitmanipulation #blog #classic #codetemplate #combination #dfs #dynamicprogramming #game #graph #greedy #heap #inspiring #interval #linkedlist #manydetails #math #palindrome #recursive #slidingwindow #stack #string #subarray #trie #twopointer #twosum binarysearch editdistance hashmap intervaldp knapsack monotone oodesign presum rectangle redo review rotatelist series sql treetraversal unionfind

Recent Posts

  • a
  • a
  • a
  • a
  • a

Recent Comments

    Archives

    Categories

    • Amusing
    • Basic
    • Easy
    • Hard
    • Life
    • Medium
    • Resource
    • Review
    • Series
    • Uncategorized
    Proudly powered by WordPress | Theme: petals by Aurorum.