Add spiral-matrix

config.json

@@ -1280,6 +1280,18 @@
             "sets"
         ]
     },
+    {
+        "uuid": "b0c7cf95-6470-4c1a-8eaa-6775310926a2",
+        "slug": "spiral-matrix",
+        "core": false,
+        "unlocked_by": null,
+        "difficulty": 2,
+        "topics": [
+            "algorithms",
+            "control-flow",
+            "lists"
+        ]
+    },
     {
       "uuid": "e7351e8e-d3ff-4621-b818-cd55cf05bffd",
       "slug": "accumulate",

exercises/spiral-matrix/README.md

@@ -0,0 +1,42 @@
+# Spiral Matrix
+
+
+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:
+
+##### Spiral matrix of size 3
+
+```plain
+1 2 3
+8 9 4
+7 6 5
+```
+
+##### Spiral matrix of size 4
+
+```plain
+ 1  2  3 4
+12 13 14 5
+11 16 15 6
+10  9  8 7
+```
+
+## Submitting Exercises
+
+Note that, when trying to submit an exercise, make sure the solution is in the `exercism/python/<exerciseName>` directory.
+
+For example, if you're submitting `bob.py` for the Bob exercise, the submit command would be something like `exercism submit <path_to_exercism_dir>/python/bob/bob.py`.
+
+For more detailed information about running tests, code style and linting,
+please see the [help page](http://exercism.io/languages/python).
+
+## Source
+
+Reddit r/dailyprogrammer challenge #320 [Easy] Spiral Ascension. [https://www.reddit.com/r/dailyprogrammer/comments/6i60lr/20170619_challenge_320_easy_spiral_ascension/](https://www.reddit.com/r/dailyprogrammer/comments/6i60lr/20170619_challenge_320_easy_spiral_ascension/)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+

exercises/spiral-matrix/example.py

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+def spiral(size):
+    sm = [[0]*size for k in range(size)]
+    i, j, el = 0, -1, 1
+    di, dj = [0, 1, 0, -1], [1, 0, -1, 0]
+    for x in range(2*size - 1):
+        for y in range((2*size - x) // 2):
+            i += di[x % 4]
+            j += dj[x % 4]
+            sm[i][j] = el
+            el += 1
+    return sm

exercises/spiral-matrix/spiral_matrix.py

@@ -0,0 +1,2 @@
+def spiral(size):
+    pass

exercises/spiral-matrix/spiral_matrix_test.py

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+import unittest
+
+from spiral_matrix import spiral
+
+
+# Tests adapted from `problem-specifications//canonical-data.json` @ v1.1.0
+
+
+class SpiralMatrixTest(unittest.TestCase):
+    def test_spiral_matrix_with_size_0(self):
+        self.assertEqual(spiral(0), [])
+
+    def test_spiral_matrix_with_size_1(self):
+        self.assertEqual(spiral(1), [[1]])
+
+    def test_spiral_matrix_with_size_2(self):
+        self.assertEqual(spiral(2), [[1, 2],
+                                     [4, 3]])
+
+    def test_spiral_matrix_with_size_3(self):
+        self.assertEqual(spiral(3), [[1, 2, 3],
+                                     [8, 9, 4],
+                                     [7, 6, 5]])
+
+    def test_spiral_matrix_with_size_4(self):
+        self.assertEqual(spiral(4), [[1,  2,  3,  4],
+                                     [12, 13, 14, 5],
+                                     [11, 16, 15, 6],
+                                     [10, 9,  8,  7]])
+
+    def test_spiral_matrix_with_size_5(self):
+        self.assertEqual(spiral(5), [[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]])
+
+
+if __name__ == '__main__':
+    unittest.main()