# HG changeset patch
# User Jordi Gutiérrez Hermoso <jordigh@octave.org>
# Date 1513227088 18000
# Node ID 56b75b62d5913a834473ab3518a87631b85ef363
# Parent  13f69301183f817bef150dbd90eca9bec5ed0c30
day 13

diff --git a/2017/day13.d b/2017/day13.d
new file mode 100644
--- /dev/null
+++ b/2017/day13.d
@@ -0,0 +1,29 @@
+import std.stdio;
+import std.algorithm: filter, map, sum;
+import std.string: split;
+import std.conv: to;
+import std.array: array;
+
+auto getHits(T)(T firewall, int init = 0) {
+  return firewall.filter!(xy => (init + xy[0]) % (2*(xy[1]-1)) == 0);
+}
+
+auto computeSeverity(T)(T firewall) {
+  return firewall.getHits.map!(xy => xy[0]*xy[1]).sum;
+}
+
+auto findPassing(T)(T firewall) {
+  auto init = 0;
+  while(! firewall.getHits(init).empty) {
+    init++;
+  }
+  return init;
+}
+
+void main(string[] args) {
+  auto firewall = File(args[1]).byLineCopy.map!(
+    x => x.split(": ").map!(to!int)
+  ).array;
+  writeln(firewall.computeSeverity);
+  writeln(firewall.findPassing);
+}