Data commit

Task/Spiral-matrix/Jq/spiral-matrix-1.jq

@@ -0,0 +1,26 @@
+# Create an m x n matrix
+ def matrix(m; n; init):
+   if m == 0 then []
+   elif m == 1 then [range(0;n)] | map(init)
+   elif m > 0 then
+     matrix(1;n;init) as $row
+     | [range(0;m)] | map( $row )
+   else error("matrix\(m);_;_) invalid")
+   end ;
+
+# Print a matrix neatly, each cell occupying n spaces
+def neatly(n):
+  def right: tostring | ( " " * (n-length) + .);
+  . as $in
+  | length as $length
+  | reduce range (0;$length) as $i
+      (""; . + reduce range(0;$length) as $j
+      (""; "\(.)\($in[$i][$j] | right )" ) + "\n" ) ;
+
+def right:
+  if   . == [1,  0] then [ 0, -1]
+  elif . == [0, -1] then [-1,  0]
+  elif . == [-1, 0] then [ 0,  1]
+  elif . == [0,  1] then [ 1,  0]
+  else error("invalid direction: \(.)")
+  end;

Task/Spiral-matrix/Jq/spiral-matrix-2.jq

@@ -0,0 +1,14 @@
+def spiral(n):
+  # we just placed m at i,j, and we are moving in the direction d
+  def _next(i; j; m; d):
+    if m == (n*n) - 1 then .
+    elif .[i+d[0]][j+d[1]] == false
+      then .[i+d[0]][j+d[1]]   = m+1 | _next(i+d[0]; j+d[1]; m+1; d)
+    else (d|right) as $d
+       |   .[i+$d[0]][j+$d[1]] = m+1 | _next(i+$d[0]; j+$d[1]; m+1; $d)
+    end;
+
+  matrix(n;n;false) | .[0][0] = 0 | _next(0;0;0; [0,1]) ;
+
+# Example
+spiral(5) | neatly(3)