Largest Island Size

You are given a 2D binary matrix with 0 and 1 entries. An island is a group of adjacent 1's connected horizontally or vertically. Your task is to find the size (i.e. the number of 1's) of the largest island in the matrix.

Formally, let \(matrix[i][j]\) denote the element in the \(i\)-th row and \(j\)-th column of the grid. Two cells \(matrix[i][j]\) and \(matrix[k][l]\) are connected if and only if \(|i-k| + |j-l| = 1\). Find the maximum size among all islands in the grid. If there is no island, return 0.

inputFormat

The input is read from standard input (stdin) and is formatted as follows:

1. The first line contains two integers \(m\) and \(n\), representing the number of rows and columns of the matrix.
2. The next \(m\) lines each contain \(n\) space-separated integers (each either 0 or 1) representing the rows of the matrix.

outputFormat

Output a single integer to standard output (stdout) indicating the size of the largest island in the matrix.

4 5
1 1 0 0 0
1 1 0 1 0
0 0 0 1 1
0 1 0 0 1

4