Solve problem 5

c++/problem5.cpp

@@ -0,0 +1,32 @@
+#include <bitset>
+#include "solutions.hpp"
+
+using namespace std;
+
+template <>
+pair<string, string> solve<5>(istream& input) {
+    uint64_t max_seatid = 0;
+    size_t part2 = 0;
+    bitset<1024> taken_seats;
+    for (string line; getline(input, line); ) {
+        uint64_t seatid = 0;
+        for (auto c : line) {
+            seatid <<= 1;
+            switch (c) {
+                case 'B':
+                case 'R':
+                    seatid++;
+            }
+        }
+        max_seatid = max(seatid, max_seatid);
+        taken_seats.set(seatid);
+    }
+    for (size_t i = 1; i < taken_seats.size(); ++i) {
+        if (taken_seats[i-1] && taken_seats[i+1] && !taken_seats[i]) {
+            part2 = i;
+            break;
+        }
+    }
+
+    return pair(to_string(max_seatid), to_string(part2));
+}