Add: Magic Squares In Grid

problems/magic-squares-in-grid/magic_squares_in_grid.go

@@ -1 +1,29 @@
 package magic_squares_in_grid
+
+func numMagicSquaresInside(grid [][]int) int {
+	ans, r, c := 0, len(grid)-1, len(grid[0])-1
+	for i := 1; i < r; i++ {
+	flag:
+		for j := 1; j < c; j++ {
+			if grid[i][j] == 5 &&
+				grid[i-1][j-1]+grid[i-1][j]+grid[i-1][j+1] == 15 &&
+				grid[i+1][j-1]+grid[i+1][j]+grid[i+1][j+1] == 15 &&
+				grid[i-1][j-1]+grid[i][j-1]+grid[i+1][j-1] == 15 &&
+				grid[i-1][j+1]+grid[i][j+1]+grid[i+1][j+1] == 15 &&
+				grid[i-1][j]+grid[i+1][j] == 10 &&
+				grid[i][j-1]+grid[i][j+1] == 10 &&
+				grid[i-1][j-1]+grid[i+1][j+1] == 10 &&
+				grid[i-1][j+1]+grid[i+1][j-1] == 10 {
+				for m := i - 1; m <= i+1; m++ {
+					for n := j - 1; n <= j+1; n++ {
+						if (m != i && n != j && grid[m][n] == 5) || grid[m][n] < 1 || grid[m][n] > 9 {
+							continue flag
+						}
+					}
+				}
+				ans++
+			}
+		}
+	}
+	return ans
+}

problems/magic-squares-in-grid/magic_squares_in_grid_test.go

@@ -1 +1,43 @@
 package magic_squares_in_grid
+
+import "testing"
+
+type caseType struct {
+	input    [][]int
+	expected int
+}
+
+func TestNumMagicSquaresInside(t *testing.T) {
+	tests := [...]caseType{
+		{
+			input: [][]int{
+				{4, 3, 8, 4},
+				{9, 5, 1, 9},
+				{2, 7, 6, 2},
+			},
+			expected: 1,
+		},
+		{
+			input: [][]int{
+				{5, 5, 5},
+				{5, 5, 5},
+				{5, 5, 5},
+			},
+			expected: 0,
+		},
+		{
+			input: [][]int{
+				{1, 8, 6},
+				{10, 5, 0},
+				{4, 2, 9},
+			},
+			expected: 0,
+		},
+	}
+	for _, tc := range tests {
+		output := numMagicSquaresInside(tc.input)
+		if output != tc.expected {
+			t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
+		}
+	}
+}