Solved Number Spiral exercise

.vscode/launch.json

@@ -0,0 +1,7 @@
+{
+  // Use IntelliSense to learn about possible attributes.
+  // Hover to view descriptions of existing attributes.
+  // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+  "version": "0.2.0",
+  "configurations": []
+}

introductory.go

@@ -104,3 +104,53 @@ func BeautifulPermutations(n int) string {
 
 	return fmt.Sprint(result)
 }
+
+func NumberSpiral(row, col int) int64 {
+	result := int64(1)
+	var size int
+
+	if row > col {
+		size = row
+	} else {
+		size = col
+	}
+
+	for i := 2; i <= size; i++ {
+		result = result + int64(2*(i-1))
+	}
+
+	switch {
+	case row == col:
+		return result
+	case col > row:
+		if col%2 == 1 {
+			return result + int64(size-row)
+		} else {
+			return result + int64(row-size)
+		}
+	case col < row:
+		if row%2 == 1 {
+			return result + int64(col-size)
+		} else {
+			return result + int64(size-col)
+		}
+	}
+
+	return 0
+
+	/*
+		maxLoops := size * size
+		i := int32(1)
+		j := int32(1)
+
+		for n := int64(1); n <= maxLoops; n++ {
+			if i == y && j == x {
+				return n
+			}
+
+
+		}
+
+		return 0
+	*/
+}

introductory_test.go

@@ -38,3 +38,21 @@ func TestBeautifulPermutations(t *testing.T) {
 	assert.Equal(t, "[9 7 5 3 1 8 6 4 2]", BeautifulPermutations(9))
 	assert.Equal(t, 48895, len(BeautifulPermutations(10000)))
 }
+
+func TestNumberSpiral(t *testing.T) {
+	assert.Equal(t, int64(8), NumberSpiral(2, 3))
+	assert.Equal(t, int64(1), NumberSpiral(1, 1))
+	assert.Equal(t, int64(15), NumberSpiral(4, 2))
+	assert.Equal(t, int64(11), NumberSpiral(2, 4))
+	assert.Equal(t, int64(13), NumberSpiral(4, 4))
+	assert.Equal(t, int64(18), NumberSpiral(5, 2))
+	assert.Equal(t, int64(24), NumberSpiral(2, 5))
+	assert.Equal(t, int64(21), NumberSpiral(5, 5))
+	assert.Equal(t, int64(19), NumberSpiral(5, 3))
+	assert.Equal(t, int64(23), NumberSpiral(3, 5))
+	assert.Equal(t, int64(889344699930098742), NumberSpiral(170550340, 943050741))
+	assert.Equal(t, int64(890061110095112626), NumberSpiral(121998376, 943430501))
+	assert.Equal(t, int64(593021767041187724), NumberSpiral(689913499, 770079066))
+	assert.Equal(t, int64(871712102163621276), NumberSpiral(586095107, 933655238))
+	assert.Equal(t, int64(999999997000000003), NumberSpiral(999_999_999, 999_999_999))
+}