[New Exercise]: Spiral Matrix

config.json

@@ -713,6 +713,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "spiral-matrix",
+        "name": "Spiral Matrix",
+        "uuid": "37534530-58c2-4993-ae27-9e743058dc8f",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "complex-numbers",
         "name": "Complex 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/SpiralMatrix.example.ps1

@@ -0,0 +1,64 @@
+Function Get-SpiralMatrix() {
+    <#
+    .SYNOPSIS
+    Implement a function to generate a spiral matrix.
+
+    .DESCRIPTION
+    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
+
+    .PARAMETER Size
+    Size of the matrix.
+
+    .EXAMPLE
+    Get-SpiralMatrix -Size 2
+    Return: @(
+        @(1,2),
+        @(4,3)
+    )
+    #>
+    [CmdletBinding()]
+    Param(
+        [int]$Size
+    )
+
+    enum Dir {
+        RIGHT
+        DOWN
+        LEFT
+        UP
+    }
+
+    $matrix = @()
+    for ($i = 0; $i -lt $Size; $i++) {
+        $matrix += ,(@($null) * $Size)
+    }
+
+    $top    = $left = 0
+    $bottom = $right = $Size - 1
+    $dir    = [Dir]::RIGHT
+    $value  = 1
+
+    while (($bottom -ge $top) -and ($right -ge $left)) {
+        switch ($dir) {
+            RIGHT   {
+                $left..$right | ForEach-Object { $matrix[$top][$_] = $value; $value++ }
+                $top++
+            }
+            DOWN    { 
+                $top..$bottom | ForEach-Object { $matrix[$_][$right] = $value; $value++ }
+                $right--
+            }
+            LEFT    {  
+                $right..$left | ForEach-Object { $matrix[$bottom][$_] = $value; $value++ }
+                $bottom--
+            }
+            default {  
+                $bottom..$top | ForEach-Object { $matrix[$_][$left] = $value; $value++ }
+                $left++
+            }
+        }
+        $dir = ($dir + 1) % 4
+    }
+    $matrix
+}

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

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "glaxxie"
+  ],
+  "files": {
+    "solution": [
+      "SpiralMatrix.ps1"
+    ],
+    "test": [
+      "SpiralMatrix.tests.ps1"
+    ],
+    "example": [
+      ".meta/SpiralMatrix.example.ps1"
+    ]
+  },
+  "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://www.reddit.com/r/dailyprogrammer/comments/6i60lr/20170619_challenge_320_easy_spiral_ascension/"
+}

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.ps1

@@ -0,0 +1,25 @@
+Function Get-SpiralMatrix() {
+    <#
+    .SYNOPSIS
+    Implement a function to generate a spiral matrix.
+
+    .DESCRIPTION
+    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
+
+    .PARAMETER Size
+    Size of the matrix.
+
+    .EXAMPLE
+    Get-SpiralMatrix -Size 2
+    Return: @(
+        @(1,2),
+        @(4,3)
+    )
+    #>
+    [CmdletBinding()]
+    Param(
+        [int]$Size
+    )
+    Throw "Please implement this function"
+}

exercises/practice/spiral-matrix/SpiralMatrix.tests.ps1

@@ -0,0 +1,68 @@
+BeforeAll {
+    . "./SpiralMatrix.ps1"
+}
+
+Describe "SpiralMatrix test cases" {
+    It "empty spiral" {
+        $got  = Get-SpiralMatrix -Size 0
+        $want = @()
+
+        $got | Should -BeExactly $want
+    }
+
+    It "trivial spiral" {
+        $got  = Get-SpiralMatrix -Size 1
+        $want = @(
+            ,@(1)
+        )
+
+        $got | Should -BeExactly $want
+    }
+
+    It "spiral of size 2" {
+        $got  = Get-SpiralMatrix -Size 2
+        $want = @(
+            @(1,2),
+            @(4,3)
+        )
+
+        $got | Should -BeExactly $want
+    }
+
+    It "spiral of size 3" {
+        $got  = Get-SpiralMatrix -Size 3
+        $want = @(
+            @(1,2,3),
+            @(8,9,4),
+            @(7,6,5)
+        )
+
+        $got | Should -BeExactly $want
+    }
+
+    It "spiral of size 4" {
+        $got  = Get-SpiralMatrix -Size 4
+        $want = @(
+            @( 1, 2, 3,4),
+            @(12,13,14,5),
+            @(11,16,15,6),
+            @(10, 9, 8,7)
+        )
+
+        $got | Should -BeExactly $want
+    }
+
+    It "spiral of size 5" {
+        $got  = Get-SpiralMatrix -Size 5
+        $want = @(
+            @( 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)
+        )
+
+        $got | Should -BeExactly $want
+    }
+
+}