Number of Islands
Updated Feb 24, 2026
Problem
Count connected components of '1' in a grid.
Constraints
1 <= m, n <= 300
Examples
Example 1
Input:
{"grid": [["1", "1", "1", "1", "0"], ["1", "1", "0", "1", "0"], ["1", "1", "0", "0", "0"], ["0", "0", "0", "0", "0"]]}
Output:
1
Function Signature
def numIslands(self, grid: list[list[str]]) -> int
How to Submit
Implement a Solution class with a numIslands method.
Your method will be called with the input parameters and should return the answer.