2017 day1

1 files changed, 35 insertions, 1 deletions

diff --git a/src/2017/day1/aoc.cpp b/src/2017/day1/aoc.cpp
index 9381e0c..b0e3558 100644
--- a/src/2017/day1/aoc.cpp
+++ b/src/2017/day1/aoc.cpp
@@ -1,3 +1,37 @@
 #include "aoc.h"
 
-namespace aoc2017 {}
+namespace aoc2017 {
+
+int day1(line_view lv) {
+  int sum{0};
+  const char* p1 = lv.line;
+  const char* p2 = p1 + 1;
+  while (*p2 >= '0' && *p2 <= '9') {
+    if (*p1 == *p2) {
+      sum += *p1 - '0';
+    }
+    p1++;
+    p2++;
+  }
+  if (*p1 == *lv.line) {
+    sum += *p1 - '0';
+  }
+  return sum;
+}
+
+int day1part2(line_view lv) {
+  int sum{0};
+  size_t size = lv.length % 2 == 0 ? lv.length : lv.length - 1;
+  const char* p1 = lv.line;
+  const char* p = lv.line + size / 2;
+  while (*p1 >= '0' && *p1 <= '9') {
+    const char* p2 = p1 < p ? (p + (p1 - lv.line)) : (lv.line + (p1 - p));
+    if (*p1 == *p2) {
+      sum += *p1 - '0';
+    }
+    p1++;
+  }
+  return sum;
+}
+
+} // namespace aoc2017