Solution for 2015 Day 3 part 2 (C++)

Signed-off-by: Sebastian Lukas <[email protected]>

2015/Day3/day3.cpp

@@ -5,9 +5,7 @@
 #include <vector>
 #include <algorithm>
 
-int main ()
-{
-
+void part1() {
     std::ifstream t("input.txt");
     std::string s_input((std::istreambuf_iterator<char>(t)),
                     std::istreambuf_iterator<char>());
@@ -43,6 +41,78 @@ int main ()
 
     positions.erase(uni, positions.end());
 
-    std::cout << positions.size() << " houses receive at least one present!\n";
+    std::cout << "Part1: " << positions.size() << " houses receive at least one present!\n";
+}
+
+void part2() {
+    std::ifstream t("input.txt");
+    std::string s_input((std::istreambuf_iterator<char>(t)),
+                    std::istreambuf_iterator<char>());
+
+    std::vector<int> positions;
+    int position_x = 0;
+    int position_y = 0;
+    int position_robo_x = 0;
+    int position_robo_y = 0;
+
+    positions.push_back(0); //First home
+
+    bool santa = true;
+
+    for(char& c : s_input) {
+
+        switch (c)
+        {
+        case '>':
+            if (santa) {
+                position_x++;
+            } else {
+                position_robo_x++;
+            }
+            break;
+        case '<':
+            if (santa) {
+                position_x--;
+            } else {
+                position_robo_x--;
+            }
+            break;
+        case '^':
+            if (santa) {
+                position_y++;
+            } else {
+                position_robo_y++;
+            }
+            break;
+        case 'v':
+            if (santa) {
+                position_y--;
+            } else {
+                position_robo_y--;
+            }
+            break;
+        }
+
+        if (santa) {
+            positions.push_back(100*position_x + position_y);
+            santa = false;
+        } else {
+            positions.push_back(100*position_robo_x + position_robo_y);
+            santa = true;
+        }
+    }
+
+    std::sort(positions.begin(), positions.end());
+
+    auto uni = std::unique(positions.begin(), positions.end());
+
+    positions.erase(uni, positions.end());
+
+    std::cout << "Part2: " << positions.size() << " houses receive at least one present!\n";
+}
 
+int main ()
+{
+    part1();
+    part2();
 }