Add spiral-matrix exercise (#196)

config.json

@@ -495,6 +495,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "spiral-matrix",
+        "name": "Spiral Matrix",
+        "uuid": "2fd887a4-bf2d-4cbe-8293-d195f7947f9e",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "armstrong-numbers",
         "name": "Armstrong Numbers",

exercises/practice/spiral-matrix/.docs/instructions.md

@@ -0,0 +1,24 @@
+# Instructions
+
+Given the size, return a square matrix of numbers in spiral order.
+
+The matrix should be filled with natural numbers, starting from 1 in the top-left corner, increasing in an inward, clockwise spiral order, like these examples:
+
+## Examples
+
+### Spiral matrix of size 3
+
+```text
+1 2 3
+8 9 4
+7 6 5
+```
+
+### Spiral matrix of size 4
+
+```text
+ 1  2  3 4
+12 13 14 5
+11 16 15 6
+10  9  8 7
+```

exercises/practice/spiral-matrix/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "spiral-matrix.v"
+    ],
+    "test": [
+      "run_test.v"
+    ],
+    "example": [
+      ".meta/example.v"
+    ]
+  },
+  "blurb": "Given the size, return a square matrix of numbers in spiral order.",
+  "source": "Reddit r/dailyprogrammer challenge #320 [Easy] Spiral Ascension.",
+  "source_url": "https://web.archive.org/web/20230607064729/https://old.reddit.com/r/dailyprogrammer/comments/6i60lr/20170619_challenge_320_easy_spiral_ascension/"
+}

exercises/practice/spiral-matrix/.meta/example.v

@@ -0,0 +1,36 @@
+module main
+
+fn spiral_matrix(size int) [][]int {
+	mut result := [][]int{len: size}
+	for i in 0 .. size {
+		result[i] = []int{len: size, init: size * size}
+	}
+
+	mut value := 1
+	mut row := 0
+	mut column := 0
+	mut side_length := size - 1
+	for side_length >= 1 {
+		for _ in 0 .. side_length {
+			result[row][column] = value++
+			column++
+		}
+		for _ in 0 .. side_length {
+			result[row][column] = value++
+			row++
+		}
+		for _ in 0 .. side_length {
+			result[row][column] = value++
+			column--
+		}
+		for _ in 0 .. side_length {
+			result[row][column] = value++
+			row--
+		}
+		row++
+		column++
+		side_length -= 2
+	}
+
+	return result
+}

exercises/practice/spiral-matrix/.meta/tests.toml

@@ -0,0 +1,21 @@
+# This is an auto-generated file. Regular comments will be removed when this
+# file is regenerated. Regenerating will not touch any manually added keys,
+# so comments can be added in a "comment" key.
+
+[8f584201-b446-4bc9-b132-811c8edd9040]
+description = "empty spiral"
+
+[e40ae5f3-e2c9-4639-8116-8a119d632ab2]
+description = "trivial spiral"
+
+[cf05e42d-eb78-4098-a36e-cdaf0991bc48]
+description = "spiral of size 2"
+
+[1c475667-c896-4c23-82e2-e033929de939]
+description = "spiral of size 3"
+
+[05ccbc48-d891-44f5-9137-f4ce462a759d]
+description = "spiral of size 4"
+
+[f4d2165b-1738-4e0c-bed0-c459045ae50d]
+description = "spiral of size 5"

exercises/practice/spiral-matrix/run_test.v

@@ -0,0 +1,51 @@
+module main
+
+fn test_empty_spiral() {
+	expect := [][]int{}
+	assert spiral_matrix(0) == expect
+}
+
+fn test_trivial_spiral() {
+	expect := [
+		[1],
+	]
+	assert spiral_matrix(1) == expect
+}
+
+fn test_spiral_of_size_2() {
+	expect := [
+		[1, 2],
+		[4, 3],
+	]
+	assert spiral_matrix(2) == expect
+}
+
+fn test_spiral_of_size_3() {
+	expect := [
+		[1, 2, 3],
+		[8, 9, 4],
+		[7, 6, 5],
+	]
+	assert spiral_matrix(3) == expect
+}
+
+fn test_spiral_of_size_4() {
+	expect := [
+		[1, 2, 3, 4],
+		[12, 13, 14, 5],
+		[11, 16, 15, 6],
+		[10, 9, 8, 7],
+	]
+	assert spiral_matrix(4) == expect
+}
+
+fn test_spiral_of_size_5() {
+	expect := [
+		[1, 2, 3, 4, 5],
+		[16, 17, 18, 19, 6],
+		[15, 24, 25, 20, 7],
+		[14, 23, 22, 21, 8],
+		[13, 12, 11, 10, 9],
+	]
+	assert spiral_matrix(5) == expect
+}

exercises/practice/spiral-matrix/spiral-matrix.v

@@ -0,0 +1,4 @@
+module main
+
+fn spiral_matrix(size int) [][]int {
+}