Data commit

Task/Spiral-matrix/Nim/spiral-matrix.nim

@@ -0,0 +1,27 @@
+import sequtils, strutils
+
+proc `$`(m: seq[seq[int]]): string =
+  for r in m:
+    let lg = result.len
+    for c in r:
+      result.addSep(" ", lg)
+      result.add align($c, 2)
+    result.add '\n'
+
+proc spiral(n: Positive): seq[seq[int]] =
+  result = newSeqWith(n, repeat(-1, n))
+  var dx = 1
+  var dy, x, y = 0
+  for i in 0 ..< (n * n):
+    result[y][x] = i
+    let (nx, ny) = (x+dx, y+dy)
+    if nx in 0 ..< n and ny in 0 ..< n and result[ny][nx] == -1:
+      x = nx
+      y = ny
+    else:
+      swap dx, dy
+      dx = -dx
+      x += dx
+      y += dy
+
+echo spiral(5)