Max Area of Island

Given a grid of 0s and 1s, return the area (cell count) of the largest island (4-directionally connected group of 1s). Print 0 if there is no island.

Example

Input:

Output: 3

Approach

Same flood-fill scan as Number of Islands, but each DFS/BFS call returns the size of the island it just explored instead of just marking it — track the maximum size seen.

Input format

Line 1: number of rows R Next R lines: space-separated grid row