AdventOfCode 2015

day1.dart

//part1
void main() {
  int floor = 0;
  for (int i = 0; i < input.length; ++i) {
    if (input[i] == ")") --floor;
    else if (input[i] == "(") ++floor;
  }
  print(floor);
}

//part2
void main() {
  int floor = 0;
  for (int i = 0; i < input.length; ++i) {
    if (input[i] == ")") --floor;
    else if (input[i] == "(") ++floor;
    if (floor == -1) {
      print(i+1);
      break;
    }
  }
}

day2.dart

// Part 1
import "dart:math";
  
void main() {
  int value = 0;
  input.split("\n").forEach((element) {
    List<int> parts = element.split("x").map((i) => int.parse(i)).toList();
    int side1 = parts[0]*parts[1];
    int side2 = parts[1]*parts[2];
    int side3 = parts[0]*parts[2];
    value += 2*side1 + 2*side2 + 2*side3 + min(min(side1, side2), side3);
  });
  print(value);
}

// Part 2
void main() {
  int value = 0;
  input.split("\n").forEach((element) {
    List<int> parts = element.split("x").map((i) => int.parse(i)).toList();
    parts.sort((a, b) => a.compareTo(b));
    value += 2*parts[0]+2*parts[1]+parts[0]*parts[1]*parts[2];
  });
  print(value);
}

day3.dart

// Part 1
void main() {
  int x = 0;
  int y = 0;
  Map<String, int> locations = Map<String, int>();
  locations[key(x,y)] = 1;
  
  input.split("").forEach((direction) {
    if (direction == "<") --x;
    else if (direction == ">") ++x;
    else if (direction == "v") --y;
    else if (direction == "^") ++y;
    if (locations[key(x,y)] == null) locations[key(x,y)] = 0;
    locations[key(x,y)] += 1;
  });
  
  print(locations.length);
}

String key(int x, int y) {
  return "$x,$y";
}

// Part 2
void main() {
  int santaX = 0;
  int santaY = 0;
  int roboX = 0;
  int roboY = 0;
  Map<String, int> locations = Map<String, int>();
  // Both deliver present before moving
  locations[key(0,0)] = 2;
  int index = 0;
  
  input.split("").forEach((direction) {
    int x;
    int y;
    // Setup our coordinates for whoever is delivering
    if (index % 2 == 0) {
      x = santaX;
      y = santaY;
    } else {
      x = roboX;
      y = roboY;
    }
    
    // Update our coordinates with a direction
    if (direction == "<") --x;
    else if (direction == ">") ++x;
    else if (direction == "v") --y;
    else if (direction == "^") ++y;
    if (locations[key(x,y)] == null) locations[key(x,y)] = 0;
    locations[key(x,y)] += 1;
    
    // Update our locations with the new coordinates
    if (index % 2 == 0) {
      santaX = x;
      santaY = y;
    } else {
      roboX = x;
      roboY = y;
    }
    
    ++index;
  });
  
  print(locations.length);
}

String key(int x, int y) {
  return "$x,$y";
}

day5.dart

// Part 1
void main() {
  int count = 0;
	input.split("\n").forEach((line) {
  	if (vowels(line) >= 3 && doubleLetters(line) && !forbiddenStrings(line)) ++count;
  });
  print(count);
}

int vowels(String str) {
  int vowels = 0;
  str.split("").forEach((l) {
    if (l == "a" || l == "e" || l == "i" || l == "o" || l == "u") ++vowels;
  });
  return vowels;
}

bool doubleLetters(String str) {
  for (int i = 0; i < str.length - 1; ++i) {
    if (str[i] == str[i+1]) return true;
  }
  return false;
}

bool forbiddenStrings(String str) {
  return str.contains("ab") || str.contains("cd") || str.contains("pq") || str.contains("xy");
}

// Part 2
void main() {
  int count = 0;
	input.split("\n").forEach((line) {
  	if (repeatedPairs(line) && repeating(line)) ++count;
  });
  print(count);
}

bool repeatedPairs(String str) {
  for (int i = 0; i < str.length - 2; ++i) {
    String search = "${str[i]}${str[i+1]}";
    if (str.contains(search, i+2)) return true;
  }
  return false;
}

bool repeating(String str) {
  for (int i = 0; i < str.length - 2; ++i) {
    if (str[i] == str[i+2]) return true;
  }
  return false;
}

day6.dart

// Part 1
enum Operation { on, off, toggle }

void main() {
  List<List<bool>> lights = List<List<bool>>(1000);
  
  for (int i = 0; i < 1000; ++i) {
    lights[i] = List<bool>(1000);
    for (int j = 0; j < 1000; ++j) {
      lights[i][j] = false;
    }
  }
  
	input.split("\n").forEach((line) {
    List<String> parts = line.split(" ");
    Operation op;
    List<int> start;
    List<int> end;
    
    if (parts[1] == "off") {
      op = Operation.off;
      start = parts[2].split(",").map((c) => int.parse(c)).toList();
      end = parts[4].split(",").map((c) => int.parse(c)).toList();
    } else if (parts[1] == "on") {
      op = Operation.on;
      start = parts[2].split(",").map((c) => int.parse(c)).toList();
      end = parts[4].split(",").map((c) => int.parse(c)).toList();
    } else if (parts[0] == "toggle") {
      op = Operation.toggle;
      start = parts[1].split(",").map((c) => int.parse(c)).toList();
      end = parts[3].split(",").map((c) => int.parse(c)).toList();
    }
    
    for (int i = start[0]; i <= end[0]; ++i) {
      for (int j = start[1]; j <= end[1]; ++j) {
        if (op == Operation.on) lights[i][j] = true;
        else if (op == Operation.off) lights[i][j] = false;
        else if (op == Operation.toggle) lights[i][j] = !lights[i][j];
      }
    }
  });
  
  int count = 0;
  
  for (int i = 0; i < 1000; ++i) {
    for (int j = 0; j < 1000; ++j) {
      if (lights[i][j]) ++count;
    }
  }
  
  print(count);
}

// Part 2
enum Operation { on, off, toggle }

void main() {
  List<List<int>> lights = List<List<int>>(1000);
  
  for (int i = 0; i < 1000; ++i) {
    lights[i] = List<int>(1000);
    for (int j = 0; j < 1000; ++j) {
      lights[i][j] = 0;
    }
  }
  
	input.split("\n").forEach((line) {
    List<String> parts = line.split(" ");
    Operation op;
    List<int> start;
    List<int> end;
    
    if (parts[1] == "off") {
      op = Operation.off;
      start = parts[2].split(",").map((c) => int.parse(c)).toList();
      end = parts[4].split(",").map((c) => int.parse(c)).toList();
    } else if (parts[1] == "on") {
      op = Operation.on;
      start = parts[2].split(",").map((c) => int.parse(c)).toList();
      end = parts[4].split(",").map((c) => int.parse(c)).toList();
    } else if (parts[0] == "toggle") {
      op = Operation.toggle;
      start = parts[1].split(",").map((c) => int.parse(c)).toList();
      end = parts[3].split(",").map((c) => int.parse(c)).toList();
    }
    
    for (int i = start[0]; i <= end[0]; ++i) {
      for (int j = start[1]; j <= end[1]; ++j) {
        if (op == Operation.on) lights[i][j] += 1;
        else if (op == Operation.off && lights[i][j] > 0) lights[i][j] -= 1;
        else if (op == Operation.toggle) lights[i][j] += 2;
      }
    }
  });
  
  int count = 0;
  
  for (int i = 0; i < 1000; ++i) {
    for (int j = 0; j < 1000; ++j) {
      count += lights[i][j];
    }
  }
  
  print(count);
}