Data commit

Task/Truncatable-primes/Nim/truncatable-primes.nim

@@ -0,0 +1,33 @@
+import sets, strutils, algorithm
+
+proc primes(n: int64): seq[int64] =
+  var multiples: HashSet[int64]
+  for i in 2..n:
+    if i notin multiples:
+      result.add i
+      for j in countup(i*i, n, i.int):
+        multiples.incl j
+
+proc truncatablePrime(n: int64): tuple[left, right: int64] =
+  var
+    primelist: seq[string]
+  for x in primes(n):
+    primelist.add($x)
+  reverse primelist
+  var primeset = primelist.toHashSet
+  for n in primelist:
+    var alltruncs: HashSet[string]
+    for i in 0..n.high:
+      alltruncs.incl n[i..n.high]
+    if alltruncs <= primeset:
+      result.left = parseInt(n)
+      break
+  for n in primelist:
+    var alltruncs: HashSet[string]
+    for i in 0..n.high:
+      alltruncs.incl n[0..i]
+    if alltruncs <= primeset:
+      result.right = parseInt(n)
+      break
+
+echo truncatablePrime(1000000i64)