Codemia | Master System Design Interviews Through Active Practice

Surrounded Regions

Given an m x n matrix board containing 'X' and 'O', capture all regions that are 4-directionally surrounded by 'X'. A region is captured by flipping all 'O's into 'X's in that surrounded region.

Surrounded Regions

Given an m x n matrix board containing 'X' and 'O', capture all regions that are 4-directionally surrounded by 'X'. A region is captured by flipping all 'O's into 'X's in that surrounded region.

Example 1:

Input: [["X","X","X","X"],["X","O","O","X"],["X","X","O","X"],["X","O","X","X"]]

Output: [["X","X","X","X"],["X","X","X","X"],["X","X","X","X"],["X","O","X","X"]]

Input

arr =[["X","X","X","X"],["X","O","O","X"],["X","X","O","X"],["X","O","X","X"]]

X

O

X

O

X

O

X

X (Captured)

O (Region)

T (Safe)

Phase: border

Mark border-connected Os as safe (T)

Variables

Variable	Value
m	4
n	4

DepthFunction Call

Stack empty

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