Add tasks for all the new languages

Task/Matrix-arithmetic/Nim/matrix-arithmetic.nim

@@ -0,0 +1,37 @@
+import sequtils, permutationsswap
+
+type Matrix[M,N: static[int]] = array[M, array[N, float]]
+
+proc det[M,N](a: Matrix[M,N]): float =
+  let n = toSeq 0..a.high
+  for sigma, sign in n.permutations:
+    var x = sign.float
+    for i in n: x *= a[i][sigma[i]]
+    result += x
+
+proc perm[M,N](a: Matrix[M,N]): float =
+  let n = toSeq 0..a.high
+  for sigma, sign in n.permutations:
+    var x = 1.0
+    for i in n: x *= a[i][sigma[i]]
+    result += x
+
+const
+  a = [ [1.0, 2.0]
+      , [3.0, 4.0]
+      ]
+  b = [ [ 1.0,  2,  3,  4]
+      , [ 4.0,  5,  6,  7]
+      , [ 7.0,  8,  9, 10]
+      , [10.0, 11, 12, 13]
+      ]
+  c = [ [ 0.0,  1,  2,  3,  4]
+      , [ 5.0,  6,  7,  8,  9]
+      , [10.0, 11, 12, 13, 14]
+      , [15.0, 16, 17, 18, 19]
+      , [20.0, 21, 22, 23, 24]
+      ]
+
+echo "perm: ", a.perm, " det: ", a.det
+echo "perm: ", b.perm, " det: ", b.det
+echo "perm: ", c.perm, " det: ", c.det