Discussion on: Advent of Code 2019 Solution Megathread - Day 3: Crossed Wires

[Esteban]

C++

Part 1

int main(){
  freopen("in.in", "r", stdin);
  map<pair<int, int>, bool> visitedPath;
  string wirePath;
  int minDistance = INT_MAX;
  // Read path
  while(getline (cin,wirePath)) {
    map<pair<int, int>, bool> currentPath;
    stringstream ss(wirePath);
    string move;
    pair<int, int> pos = {0,0};
    // Read moves
    while (getline(ss, move, ',')) {
      char direction = move.front();
      move.erase(move.begin());
      int distance = stoi(move);
      while(distance--){
        switch (direction) {
        case 'U': pos.first++; break;
        case 'D': pos.first--; break;
        case 'R': pos.second++; break;
        case 'L': pos.second--; break;
        }
        if(visitedPath[pos] && !currentPath[pos]){
          minDistance = min(minDistance, abs(pos.first) + abs(pos.second));
        }
        currentPath[pos] = true;
        visitedPath[pos] =  true;
      }
    }
  }
  cout<<minDistance<<endl;
  return 0;
}

Part 2

int main(){
  freopen("in.in", "r", stdin);
  map<pair<int, int>, int> visitedPath;
  string wirePath;
  int minDistance = INT_MAX;
  // Read path
  while(getline (cin,wirePath)) {
    map<pair<int, int>, bool> currentPath;
    stringstream ss(wirePath);
    string move;
    pair<int, int> pos = {0,0};
    int totalDistance = 0;
    // Read moves
    while (getline(ss, move, ',')) {
      char direction = move.front();
      move.erase(move.begin());
      int distance = stoi(move);
      while(distance--){
        totalDistance++;
        switch (direction) {
        case 'U': pos.first++; break;
        case 'D': pos.first--; break;
        case 'R': pos.second++; break;
        case 'L': pos.second--; break;
        }
        if(visitedPath[pos] != 0 && !currentPath[pos]){
          minDistance = min(minDistance, totalDistance + visitedPath[pos]);
        }
        currentPath[pos] = true;
        visitedPath[pos] = totalDistance;
      }
    }
  }
  cout<<minDistance<<endl;
  return 0;
}

[Jorge Gomez]

Beautiful code Sr. Really straight forward and easy to read and understand.