Data commit

Task/Zig-zag-matrix/Maxima/zig-zag-matrix.maxima

@@ -0,0 +1,22 @@
+zigzag(n) := block([a, i, j],
+a: zeromatrix(n, n),
+i: 1,
+j: 1,
+for k from 0 thru n*n - 1 do (
+   a[i, j]: k,
+   if evenp(i + j) then (
+      if j < n then j: j + 1 else i: i + 2,
+      if i > 1 then i: i - 1
+   ) else (
+      if i < n then i: i + 1 else j: j + 2,
+      if j > 1 then j: j - 1
+   )
+),
+a)$
+
+zigzag(5);
+/* matrix([ 0,  1,  5,  6, 14],
+          [ 2,  4,  7, 13, 15],
+          [ 3,  8, 12, 16, 21],
+          [ 9, 11, 17, 20, 22],
+          [10, 18, 19, 23, 24]) */