Add spiral-matrix

config.json

@@ -1056,6 +1056,19 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 7
+      },
+      {
+        "slug": "spiral-matrix",
+        "name": "Spiral Matrix",
+        "uuid": "2e5f7544-68fc-4993-9ee0-27b74b1176e7",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4,
+        "topics": [
+          "arrays",
+          "control_flow_loops",
+          "pointers"
+        ]
       }
     ]
   },

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 +1,20 @@
+{
+  "authors": ["ryanplusplus"],
+  "contributors": ["wolf99"],
+  "files": {
+    "solution": [
+      "spiral_matrix.c",
+      "spiral_matrix.h"
+    ],
+    "test": [
+      "test_spiral_matrix.c"
+    ],
+    "example": [
+      ".meta/example.c",
+      ".meta/example.h"
+    ]
+  },
+  "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.c

@@ -0,0 +1,50 @@
+#include <stdlib.h>
+#include "spiral_matrix.h"
+
+spiral_matrix_t *spiral_matrix_create(int size)
+{
+   spiral_matrix_t *spiral = calloc(1, sizeof(spiral_matrix_t));
+   spiral->size = size;
+
+   if (size == 0) {
+      return spiral;
+   }
+
+   spiral->matrix = calloc(size, sizeof(int *));
+   for (int i = 0; i < size; i++) {
+      spiral->matrix[i] = calloc(size, sizeof(int));
+   }
+
+   int x = 0;
+   int y = 0;
+   int dx = 1;
+   int dy = 0;
+
+   for (int i = 1; i <= size * size; i++) {
+      spiral->matrix[y][x] = i;
+      if (x + dx >= size || x + dx < 0 || y + dy >= size || y + dy < 0 ||
+          spiral->matrix[y + dy][x + dx] != 0) {
+         int new_dx = -dy;
+         int new_dy = dx;
+         dx = new_dx;
+         dy = new_dy;
+      }
+      x += dx;
+      y += dy;
+   }
+
+   return spiral;
+}
+
+void spiral_matrix_destroy(spiral_matrix_t *spiral)
+{
+   for (int i = 0; i < spiral->size; i++) {
+      free(spiral->matrix[i]);
+   }
+
+   if (spiral->size > 0) {
+      free(spiral->matrix);
+   }
+
+   free(spiral);
+}

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

@@ -0,0 +1,12 @@
+#ifndef SPIRAL_MATRIX_H
+#define SPIRAL_MATRIX_H
+
+typedef struct {
+   int size;
+   int **matrix;
+} spiral_matrix_t;
+
+spiral_matrix_t *spiral_matrix_create(int size);
+void spiral_matrix_destroy(spiral_matrix_t *spiral_matrix);
+
+#endif

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/makefile

@@ -0,0 +1,37 @@
+### If you wish to use extra libraries (math.h for instance),
+### add their flags here (-lm in our case) in the "LIBS" variable.
+
+LIBS = -lm
+
+###
+CFLAGS  = -std=c99
+CFLAGS += -g
+CFLAGS += -Wall
+CFLAGS += -Wextra
+CFLAGS += -pedantic
+CFLAGS += -Werror
+CFLAGS += -Wmissing-declarations
+CFLAGS += -DUNITY_SUPPORT_64 -DUNITY_OUTPUT_COLOR
+
+ASANFLAGS  = -fsanitize=address
+ASANFLAGS += -fno-common
+ASANFLAGS += -fno-omit-frame-pointer
+
+.PHONY: test
+test: tests.out
+	@./tests.out
+
+.PHONY: memcheck
+memcheck: ./*.c ./*.h
+	@echo Compiling $@
+	@$(CC) $(ASANFLAGS) $(CFLAGS) test-framework/unity.c ./*.c -o memcheck.out $(LIBS)
+	@./memcheck.out
+	@echo "Memory check passed"
+
+.PHONY: clean
+clean:
+	rm -rf *.o *.out *.out.dSYM
+
+tests.out: ./*.c ./*.h
+	@echo Compiling $@
+	@$(CC) $(CFLAGS) test-framework/unity.c ./*.c -o tests.out $(LIBS)

exercises/practice/spiral-matrix/spiral_matrix.c

@@ -0,0 +1 @@
+#include "spiral_matrix.h"

exercises/practice/spiral-matrix/spiral_matrix.h

@@ -0,0 +1,9 @@
+#ifndef SPIRAL_MATRIX_H
+#define SPIRAL_MATRIX_H
+
+typedef struct {
+   int size;
+   int **matrix;
+} spiral_matrix_t;
+
+#endif