# HG changeset patch
# User Jordi Gutiérrez Hermoso <jordigh@octave.org>
# Date 1512665082 18000
# Node ID 0fa6cd63af216b121bece0aadac3baad1c9bbf8a

day 1

diff --git a/2017/01/app.d b/2017/01/app.d
new file mode 100644
--- /dev/null
+++ b/2017/01/app.d
@@ -0,0 +1,38 @@
+import std.getopt;
+import std.stdio;
+import std.conv: to;
+import std.traits: isNumeric;
+
+numType day1(numType)(string input, size_t stride = 0)
+  if(isNumeric!numType)
+{
+  auto n = input.length;
+  if(stride == 0) {
+    stride = n/2;
+  }
+  int sum = 0;
+  foreach(idx, c; input) {
+    auto prev = input[(idx + stride)%n];
+    if (c == prev) {
+      sum += to!(numType)(c - '0');
+    }
+  }
+  return sum;
+}
+
+void main(string[] args) {
+  string input;
+  auto opts = getopt(
+    args,
+    "input|i", "Input captcha to process", &input
+  );
+
+  if (opts.helpWanted) {
+    defaultGetoptPrinter("Day 1 of AoC", opts.options);
+  }
+
+  auto result1 = day1!(int)(input, 1);
+  auto result2 = day1!(int)(input);
+  writeln(result1);
+  writeln(result2);
+}