Add Spiral Matrix Exercise (#625)

Author: tomasnorre

config.json

@@ -1156,6 +1156,14 @@
         "prerequisites": [],
         "difficulty": 6
       },
+      {
+        "slug": "spiral-matrix",
+        "name": "Spiral Matrix",
+        "uuid": "a8d52588-a7af-4543-867b-17f9728df77e",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "zebra-puzzle",
         "name": "Zebra Puzzle",

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": [
+    "tomasnorre"
+  ],
+  "files": {
+    "solution": [
+      "SpiralMatrix.php"
+    ],
+    "test": [
+      "SpiralMatrixTest.php"
+    ],
+    "example": [
+      ".meta/example.php"
+    ]
+  },
+  "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.php

@@ -0,0 +1,80 @@
+<?php
+
+/*
+ * By adding type hints and enabling strict type checking, code can become
+ * easier to read, self-documenting and reduce the number of potential bugs.
+ * By default, type declarations are non-strict, which means they will attempt
+ * to change the original type to match the type specified by the
+ * type-declaration.
+ *
+ * In other words, if you pass a string to a function requiring a float,
+ * it will attempt to convert the string value to a float.
+ *
+ * To enable strict mode, a single declare directive must be placed at the top
+ * of the file.
+ * This means that the strictness of typing is configured on a per-file basis.
+ * This directive not only affects the type declarations of parameters, but also
+ * a function's return type.
+ *
+ * For more info review the Concept on strict type checking in the PHP track
+ * <link>.
+ *
+ * To disable strict typing, comment out the directive below.
+ */
+
+declare(strict_types=1);
+
+class SpiralMatrix
+{
+    public function draw(int $n): array
+    {
+        // Initialize the matrix with zeros
+        $matrix = array_fill(0, $n, array_fill(0, $n, 0));
+
+        // Define boundaries
+        $top = 0;
+        $bottom = $n - 1;
+        $left = 0;
+        $right = $n - 1;
+
+        // Define direction (right, down, left, up)
+        $direction = 0;
+
+        // Initialize counter
+        $counter = 1;
+
+        // Generate the spiral matrix
+        while ($top <= $bottom && $left <= $right) {
+            if ($direction === 0) {
+                // Move from left to right
+                for ($i = $left; $i <= $right; ++$i) {
+                    $matrix[$top][$i] = $counter++;
+                }
+                ++$top;
+            } elseif ($direction === 1) {
+                // Move from top to bottom
+                for ($i = $top; $i <= $bottom; ++$i) {
+                    $matrix[$i][$right] = $counter++;
+                }
+                --$right;
+            } elseif ($direction === 2) {
+                // Move from right to left
+                for ($i = $right; $i >= $left; --$i) {
+                    $matrix[$bottom][$i] = $counter++;
+                }
+                --$bottom;
+            } elseif ($direction === 3) {
+                // Move from bottom to top
+                for ($i = $bottom; $i >= $top; --$i) {
+                    $matrix[$i][$left] = $counter++;
+                }
+                ++$left;
+            }
+
+            // Update direction
+            $direction = ($direction + 1) % 4;
+        }
+
+        return $matrix;
+    }
+}

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

@@ -0,0 +1,28 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via 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/SpiralMatrix.php

@@ -0,0 +1,33 @@
+<?php
+
+/*
+ * By adding type hints and enabling strict type checking, code can become
+ * easier to read, self-documenting and reduce the number of potential bugs.
+ * By default, type declarations are non-strict, which means they will attempt
+ * to change the original type to match the type specified by the
+ * type-declaration.
+ *
+ * In other words, if you pass a string to a function requiring a float,
+ * it will attempt to convert the string value to a float.
+ *
+ * To enable strict mode, a single declare directive must be placed at the top
+ * of the file.
+ * This means that the strictness of typing is configured on a per-file basis.
+ * This directive not only affects the type declarations of parameters, but also
+ * a function's return type.
+ *
+ * For more info review the Concept on strict type checking in the PHP track
+ * <link>.
+ *
+ * To disable strict typing, comment out the directive below.
+ */
+
+declare(strict_types=1);
+
+class SpiralMatrix
+{
+    public function draw(int $n): array
+    {
+        throw new \BadMethodCallException(sprintf('Implement the %s method', __FUNCTION__));
+    }
+}

exercises/practice/spiral-matrix/SpiralMatrixTest.php

@@ -0,0 +1,120 @@
+<?php
+
+/*
+ * By adding type hints and enabling strict type checking, code can become
+ * easier to read, self-documenting and reduce the number of potential bugs.
+ * By default, type declarations are non-strict, which means they will attempt
+ * to change the original type to match the type specified by the
+ * type-declaration.
+ *
+ * In other words, if you pass a string to a function requiring a float,
+ * it will attempt to convert the string value to a float.
+ *
+ * To enable strict mode, a single declare directive must be placed at the top
+ * of the file.
+ * This means that the strictness of typing is configured on a per-file basis.
+ * This directive not only affects the type declarations of parameters, but also
+ * a function's return type.
+ *
+ * For more info review the Concept on strict type checking in the PHP track
+ * <link>.
+ *
+ * To disable strict typing, comment out the directive below.
+ */
+
+declare(strict_types=1);
+
+use PHPUnit\Framework\TestCase;
+
+class SpiralMatrixTest extends TestCase
+{
+    private SpiralMatrix $spiralMatrix;
+
+    public static function setUpBeforeClass(): void
+    {
+        require_once 'SpiralMatrix.php';
+    }
+
+    public function setUp(): void
+    {
+        $this->spiralMatrix = new SpiralMatrix();
+    }
+
+    /**
+     * uuid: 8f584201-b446-4bc9-b132-811c8edd9040
+     */
+    public function testEmptySpiral(): void
+    {
+        $expected = [];
+        $actual = $this->spiralMatrix->draw(0);
+        $this->assertEquals($expected, $actual);
+    }
+
+    /**
+     * uuid: e40ae5f3-e2c9-4639-8116-8a119d632ab2
+     */
+    public function testTrivialSpiral(): void
+    {
+        $expected = [[1]];
+        $actual = $this->spiralMatrix->draw(1);
+        $this->assertEquals($expected, $actual);
+    }
+
+    /**
+     * uuid: cf05e42d-eb78-4098-a36e-cdaf0991bc48
+     */
+    public function testSpiralOfSize2(): void
+    {
+        $expected = [
+            [1, 2],
+            [4, 3],
+        ];
+        $actual = $this->spiralMatrix->draw(2);
+        $this->assertEquals($expected, $actual);
+    }
+
+    /**
+     * uuid: 1c475667-c896-4c23-82e2-e033929de939
+     */
+    public function testSpiralOfSize3(): void
+    {
+        $expected = [
+            [1, 2, 3],
+            [8, 9, 4],
+            [7, 6, 5],
+        ];
+        $actual = $this->spiralMatrix->draw(3);
+        $this->assertEquals($expected, $actual);
+    }
+
+    /**
+     * uuid: 05ccbc48-d891-44f5-9137-f4ce462a759d
+     */
+    public function testSpiralOfSize4(): void
+    {
+        $expected = [
+            [1, 2, 3, 4],
+            [12, 13, 14, 5],
+            [11, 16, 15, 6],
+            [10, 9, 8, 7],
+        ];
+        $actual = $this->spiralMatrix->draw(4);
+        $this->assertEquals($expected, $actual);
+    }
+
+    /**
+     * uuid: f4d2165b-1738-4e0c-bed0-c459045ae50d
+     */
+    public function testSpiralOfSize5(): void
+    {
+        $expected = [
+            [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],
+        ];
+        $actual = $this->spiralMatrix->draw(5);
+        $this->assertEquals($expected, $actual);
+    }
+}