solution.go

package main

import "fmt"

func maxAreaOfIsland(grid [][]int) int {
	var max int
	for i := 0; i < len(grid); i++ {
		for j := 0; j < len(grid[i]); j++ {
			if grid[i][j] == 1 {
				result := dfs(grid, i, j)
				if result > max {
					max = result
				}
			}
		}
	}
	return max
}

func dfs(grid [][]int, i, j int) int {
	if i < 0 || i >= len(grid) || j < 0 || j >= len(grid[i]) || grid[i][j] == 0 {
		return 0
	}
	grid[i][j] = 0
	count := 1
	count += dfs(grid, i+1, j)
	count += dfs(grid, i-1, j)
	count += dfs(grid, i, j+1)
	count += dfs(grid, i, j-1)
	return count
}

func main() {
	grid := [][]int{
		{0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0},
		{0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0},
		{0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0},
		{0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0},
		{0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0},
		{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0},
		{0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0},
		{0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0},
	}
	fmt.Println(maxAreaOfIsland(grid))
}