1 files changed, 37 insertions, 0 deletions
diff --git a/src/2017/day2/aoc.cpp b/src/2017/day2/aoc.cpp
index ed2d9d3..9069bd3 100644
--- a/src/2017/day2/aoc.cpp
+++ b/src/2017/day2/aoc.cpp
@@ -2,4 +2,41 @@
 
 namespace aoc2017 {
 
+int get_number(const char** pp) {
+  const char* p = *pp;
+  int d{0};
+  while (*p >= '0' && *p <= '9') {
+    d = d * 10 + *p - '0';
+    p++;
+  }
+  *pp = p;
+  return d;
 }
+
+int diff(line_view lv) {
+  int max{INT_MIN};
+  int min{INT_MAX};
+  const char* p = lv.line;
+  while (p < lv.line + lv.length) {
+    if (*p >= '0' && *p <= '9') {
+      int d = get_number(&p);
+      if (d > max)
+        max = d;
+      if (d < min)
+        min = d;
+    }
+    p++;
+  }
+  return max - min;
+}
+
+int day2(line_view file) {
+  int sum{0};
+  per_line(file, [&sum](line_view lv) {
+    sum += diff(lv);
+    return true;
+  });
+  return sum;
+}
+
+} // namespace aoc2017