Merge pull request #72 from arunsathiya/solve/200-number-of-islands

200. Number Of Islands

src/200-number-of-islands/main.go

@@ -0,0 +1,25 @@
+package main
+
+func dfs(i, j int, grid [][]byte) {
+	if i > len(grid)-1 || i < 0 || j < 0 || j > len(grid[0])-1 || string(grid[i][j]) != "1" {
+		return
+	}
+	grid[i][j] = '#'
+	dfs(i+1, j, grid)
+	dfs(i-1, j, grid)
+	dfs(i, j+1, grid)
+	dfs(i, j-1, grid)
+}
+
+func numIslands(grid [][]byte) int {
+	c := 0
+	for i, row := range grid {
+		for j, v := range row {
+			if string(v) == "1" {
+				c++
+				dfs(i, j, grid)
+			}
+		}
+	}
+	return c
+}

src/200-number-of-islands/main_test.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"testing"
+)
+
+func TestNumIslands(t *testing.T) {
+	tests := []struct {
+		grid   [][]byte
+		expect int
+	}{
+		{
+			grid: [][]byte{
+				[]byte("11110"),
+				[]byte("11010"),
+				[]byte("11000"),
+				[]byte("00000"),
+			},
+			expect: 1,
+		},
+		{
+			grid: [][]byte{
+				[]byte("11000"),
+				[]byte("11000"),
+				[]byte("00100"),
+				[]byte("00011"),
+			},
+			expect: 3,
+		},
+	}
+
+	for _, test := range tests {
+		actual := numIslands(test.grid)
+		if actual != test.expect {
+			t.Errorf("For grid %v, expected %d islands, but got %d", test.grid, test.expect, actual)
+		}
+	}
+}