Shortest Bridge

arraydepth-first searchbreadth-first search

You are given an n x n binary matrix grid where 1 represents land and 0 represents water.

An island is a 4-directionally connected group of 1 's not connected to any other 1 's. There are exactly two islands in grid .

You may change 0 's to 1 's to connect the two islands to form one island .

Return the smallest number of 0 's you must flip to connect the two islands .

Example 1

Input: grid = [[0,1],[1,0]]
Output: 1

Example 2

Input: grid = [[0,1,0],[0,0,0],[0,0,1]]
Output: 2

Example 3

Input: grid = [[1,1,1,1,1],[1,0,0,0,1],[1,0,1,0,1],[1,0,0,0,1],[1,1,1,1,1]]
Output: 1

n == grid.length == grid[i].length

2 <= n <= 100

grid[i][j] is either 0 or 1 .

There are exactly two islands in grid .

🤔

Medium

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicDepth-First Search