Add 2016 day 13 cpp

2016/README.md

@@ -16,7 +16,7 @@ This folder contains solutions to each of the problems in Advent of Code 2016 in
 | <nobr> [Day 10: Balance Bots](https://adventofcode.com/2016/day/10) </nobr> | <nobr> [Part 1](/2016/cpp/day_10a.cpp) [Part 2](/2016/cpp/day_10b.cpp) </nobr> |[Link](/2016/input/day_10_input)|[Link](/2016/sample_input/day_10_sample_input)|[Link](/2016/puzzles/day_10_puzzle)|
 | <nobr> [Day 11: Radioisotope Thermoelectric Generators](https://adventofcode.com/2016/day/11) </nobr> | <nobr> [Part 1](/2016/cpp/day_11a.cpp) [Part 2](/2016/cpp/day_11b.cpp) </nobr> |[Link](/2016/input/day_11_input)|[Link](/2016/sample_input/day_11_sample_input)|[Link](/2016/puzzles/day_11_puzzle)|
 | <nobr> [Day 12: Leonardo's Monorail](https://adventofcode.com/2016/day/12) </nobr> | <nobr> [Part 1](/2016/cpp/day_12a.cpp) [Part 2](/2016/cpp/day_12b.cpp) </nobr> |[Link](/2016/input/day_12_input)|[Link](/2016/sample_input/day_12_sample_input)|[Link](/2016/puzzles/day_12_puzzle)|
-| <nobr> [Day 13: ](https://adventofcode.com/2016/day/13) </nobr> | <nobr> [Part 1](/2016/cpp/day_13a.cpp) [Part 2](/2016/cpp/day_13b.cpp) </nobr> |[Link](/2016/input/day_13_input)|[Link](/2016/sample_input/day_13_sample_input)|[Link](/2016/puzzles/day_13_puzzle)|
+| <nobr> [Day 13: A Maze of Twisty Little Cubicles](https://adventofcode.com/2016/day/13) </nobr> | <nobr> [Part 1](/2016/cpp/day_13a.cpp) [Part 2](/2016/cpp/day_13b.cpp) </nobr> |[Link](/2016/input/day_13_input)|[Link](/2016/sample_input/day_13_sample_input)|[Link](/2016/puzzles/day_13_puzzle)|
 | <nobr> [Day 14: ](https://adventofcode.com/2016/day/14) </nobr> | <nobr> [Part 1](/2016/cpp/day_14a.cpp) [Part 2](/2016/cpp/day_14b.cpp) </nobr> |[Link](/2016/input/day_14_input)|[Link](/2016/sample_input/day_14_sample_input)|[Link](/2016/puzzles/day_14_puzzle)|
 | <nobr> [Day 15: ](https://adventofcode.com/2016/day/15) </nobr> | <nobr> [Part 1](/2016/cpp/day_15a.cpp) [Part 2](/2016/cpp/day_15b.cpp) </nobr> |[Link](/2016/input/day_15_input)|[Link](/2016/sample_input/day_15_sample_input)|[Link](/2016/puzzles/day_15_puzzle)|
 | <nobr> [Day 16: ](https://adventofcode.com/2016/day/16) </nobr> | <nobr> [Part 1](/2016/cpp/day_16a.cpp) [Part 2](/2016/cpp/day_16b.cpp) </nobr> |[Link](/2016/input/day_16_input)|[Link](/2016/sample_input/day_16_sample_input)|[Link](/2016/puzzles/day_16_puzzle)|

2016/cpp/day_13a.cpp

@@ -0,0 +1,119 @@
+#include <array>
+#include <fstream>
+#include <iostream>
+#include <queue>
+#include <string>
+#include <unordered_set> 
+
+enum class Type {
+    WALL, SPACE
+};
+
+int sv_to_int (const std::string_view sv) {
+  bool negative = (sv[0] == '-') ? true : false;
+  int n = 0;
+  for (int i = negative ? 1 : 0; i < sv.size(); i++) {
+    n = n * 10 + (sv[i] - '0');
+  }
+  if (negative) {
+    n *= -1;
+  }
+  return n;
+}
+
+std::array<int, 31> get_bit_masks () {
+    std::array<int, 31> bit_masks;
+    int bit_mask = 1;
+    for (int i = 0; i < 31; i++) {
+        bit_masks[i] = bit_mask;
+        bit_mask <<= 1;
+    }
+    return bit_masks;
+}
+
+struct Point {
+    Point (const int x, const int y) : x(x), y(y) {}
+    int x;
+    int y;
+};
+
+struct PointAndMove {
+    PointAndMove(const int x = 0, const int y = 0, const int move = 0) : p(Point(x, y)), move(move) {}
+    Point p;
+    int move;
+    bool operator == (const PointAndMove& pm) const {
+        return p.x == pm.p.x && p.y == pm.p.y;
+    }
+};
+
+struct pm_hasher {
+    std::size_t operator () (const PointAndMove& pm) const {
+        return pm.p.x << 5 + pm.p.y;
+    }
+};
+
+int main(int argc, char* argv[]) {
+  std::string input = "../input/day_13_input";
+  if (argc > 1) {
+    input = argv[1];
+  }
+
+  std::ifstream file(input);
+  std::string line;
+  std::getline(file, line);
+  const int designers_fav_n = std::stoi(line);
+  const std::array<int, 31> bit_masks = get_bit_masks();
+  const auto get_type = [designers_fav_n, &bit_masks](const int y, const int x) {
+    const int n = x*x + 3*x + 2*x*y + y + y*y + designers_fav_n;
+    int count = 0;
+    for (const auto& bit_mask : bit_masks) {
+        // std::cout << bit_mask << '\n';
+        count += ((n & bit_mask) != 0) ? 1 : 0;
+    }
+    // std::cout << '(' << x << ',' << y << " | " << n << " | " << count << " | " << static_cast<int>((count % 2 == 0) ? Type::SPACE : Type::WALL) << '\n'; 
+    return (count % 2 == 0) ? Type::SPACE : Type::WALL;
+  };
+  const std::array<Point, 4> moves {
+    Point(0,1),
+    Point(1,0),
+    Point(0,-1),
+    Point(-1, 0)
+  };
+  const auto in_bounds = [](const Point& p) {
+    return p.x >= 0 && p.y >= 0;
+  };
+  std::unordered_set<PointAndMove, pm_hasher> seen;
+  std::queue<PointAndMove> q;
+  PointAndMove pm;
+  pm.p = Point(1,1);
+  pm.move = 0;
+  q.push(pm);
+  // for (int i = 0; i < 10; i++) {
+  //   for (int j = 0; j < 10; j++) {
+  //       std::cout << ((get_type(i, j) == Type::WALL) ? '#' :  '.');
+  //   }
+  //   std::cout << '\n';
+  // }
+  while(!q.empty()) {
+    const auto current = q.front();
+    q.pop();
+    if (seen.find(current) != seen.end()) continue;
+    seen.insert(current);
+    if (current.p.x == 39 && current.p.y == 31) {
+        // std::cout << "Found" << '\n';
+        std::cout << current.move << '\n';
+        return 0;
+    }
+    for (const auto& move : moves) {
+        PointAndMove next;
+        next.p = Point(current.p.x + move.x, current.p.y + move.y);
+        next.move = current.move + 1;
+        if (!in_bounds(next.p)) continue;
+        if (get_type(next.p.x, next.p.y) == Type::WALL) continue;
+        if (seen.find(next) != seen.end()) continue;
+        q.push(next);
+    }
+  }
+  std::cout << "Not found " << '\n';
+  return 0;
+}

2016/cpp/day_13b.cpp

@@ -0,0 +1,118 @@
+#include <array>
+#include <fstream>
+#include <iostream>
+#include <queue>
+#include <string>
+#include <unordered_set> 
+
+enum class Type {
+    WALL, SPACE
+};
+
+int sv_to_int (const std::string_view sv) {
+  bool negative = (sv[0] == '-') ? true : false;
+  int n = 0;
+  for (int i = negative ? 1 : 0; i < sv.size(); i++) {
+    n = n * 10 + (sv[i] - '0');
+  }
+  if (negative) {
+    n *= -1;
+  }
+  return n;
+}
+
+std::array<int, 31> get_bit_masks () {
+    std::array<int, 31> bit_masks;
+    int bit_mask = 1;
+    for (int i = 0; i < 31; i++) {
+        bit_masks[i] = bit_mask;
+        bit_mask <<= 1;
+    }
+    return bit_masks;
+}
+
+struct Point {
+    Point (const int x, const int y) : x(x), y(y) {}
+    int x;
+    int y;
+};
+
+struct PointAndMove {
+    PointAndMove(const int x = 0, const int y = 0, const int move = 0) : p(Point(x, y)), move(move) {}
+    Point p;
+    int move;
+    bool operator == (const PointAndMove& pm) const {
+        return p.x == pm.p.x && p.y == pm.p.y;
+    }
+};
+
+struct pm_hasher {
+    std::size_t operator () (const PointAndMove& pm) const {
+        return pm.p.x << 5 + pm.p.y;
+    }
+};
+
+int main(int argc, char* argv[]) {
+  std::string input = "../input/day_13_input";
+  if (argc > 1) {
+    input = argv[1];
+  }
+
+  std::ifstream file(input);
+  std::string line;
+  std::getline(file, line);
+  const int designers_fav_n = std::stoi(line);
+  const std::array<int, 31> bit_masks = get_bit_masks();
+  const auto get_type = [designers_fav_n, &bit_masks](const int y, const int x) {
+    const int n = x*x + 3*x + 2*x*y + y + y*y + designers_fav_n;
+    int count = 0;
+    for (const auto& bit_mask : bit_masks) {
+        // std::cout << bit_mask << '\n';
+        count += ((n & bit_mask) != 0) ? 1 : 0;
+    }
+    // std::cout << '(' << x << ',' << y << " | " << n << " | " << count << " | " << static_cast<int>((count % 2 == 0) ? Type::SPACE : Type::WALL) << '\n'; 
+    return (count % 2 == 0) ? Type::SPACE : Type::WALL;
+  };
+  const std::array<Point, 4> moves {
+    Point(0,1),
+    Point(1,0),
+    Point(0,-1),
+    Point(-1, 0)
+  };
+  const auto in_bounds = [](const Point& p) {
+    return p.x >= 0 && p.y >= 0;
+  };
+  std::unordered_set<PointAndMove, pm_hasher> seen;
+  std::queue<PointAndMove> q;
+  PointAndMove pm;
+  pm.p = Point(1,1);
+  pm.move = 0;
+  q.push(pm);
+//   for (int i = 0; i < 10; i++) {
+//     for (int j = 0; j < 10; j++) {
+//         std::cout << ((get_type(i, j) == Type::WALL) ? '#' :  '.');
+//     }
+//     std::cout << '\n';
+//   }
+  while(!q.empty()) {
+    const auto current = q.front();
+    q.pop();
+    if (seen.find(current) != seen.end()) continue;
+    if (current.move > 50) {
+        std::cout << seen.size() << '\n';
+        return 0;
+    }
+    seen.insert(current);
+    for (const auto& move : moves) {
+        PointAndMove next;
+        next.p = Point(current.p.x + move.x, current.p.y + move.y);
+        next.move = current.move + 1;
+        if (!in_bounds(next.p)) continue;
+        if (get_type(next.p.x, next.p.y) == Type::WALL) continue;
+        if (seen.find(next) != seen.end()) continue;
+        q.push(next);
+    }
+  }
+  std::cout << "Not found " << '\n';
+  return 0;
+}

2016/input/day_13_input

@@ -0,0 +1 @@
+1352

2016/puzzles/day_13_puzzle

@@ -0,0 +1,42 @@
+--- Day 13: A Maze of Twisty Little Cubicles ---
+You arrive at the first floor of this new building to discover a much less welcoming environment than the shiny atrium of the last one. Instead, you are in a maze of twisty little cubicles, all alike.
+
+Every location in this area is addressed by a pair of non-negative integers (x,y). Each such coordinate is either a wall or an open space. You can't move diagonally. The cube maze starts at 0,0 and seems to extend infinitely toward positive x and y; negative values are invalid, as they represent a location outside the building. You are in a small waiting area at 1,1.
+
+While it seems chaotic, a nearby morale-boosting poster explains, the layout is actually quite logical. You can determine whether a given x,y coordinate will be a wall or an open space using a simple system:
+
+Find x*x + 3*x + 2*x*y + y + y*y.
+Add the office designer's favorite number (your puzzle input).
+Find the binary representation of that sum; count the number of bits that are 1.
+If the number of bits that are 1 is even, it's an open space.
+If the number of bits that are 1 is odd, it's a wall.
+For example, if the office designer's favorite number were 10, drawing walls as # and open spaces as ., the corner of the building containing 0,0 would look like this:
+
+  0123456789
+0 .#.####.##
+1 ..#..#...#
+2 #....##...
+3 ###.#.###.
+4 .##..#..#.
+5 ..##....#.
+6 #...##.###
+Now, suppose you wanted to reach 7,4. The shortest route you could take is marked as O:
+
+  0123456789
+0 .#.####.##
+1 .O#..#...#
+2 #OOO.##...
+3 ###O#.###.
+4 .##OO#OO#.
+5 ..##OOO.#.
+6 #...##.###
+Thus, reaching 7,4 would take a minimum of 11 steps (starting from your current location, 1,1).
+
+What is the fewest number of steps required for you to reach 31,39?
+
+Your puzzle answer was 90.
+
+--- Part Two ---
+How many locations (distinct x,y coordinates, including your starting location) can you reach in at most 50 steps?
+
+Your puzzle answer was 135.

2016/sample_input/day_13_sample_input

@@ -0,0 +1 @@
+10

README.md

@@ -13,7 +13,7 @@ This repository contains solutions to the Advent of Code puzzles.
 |2019  |1-25 |1-7 | [Link](/2019/) |[Link](/2019/README.md) |
 |2018  |1-25 | - | [Link](/2018/) |[Link](/2018/README.md) |
 |2017  |1-25 | - | [Link](/2017/) |[Link](/2017/README.md) |
-|2017  |1-12 | - | [Link](/2016/) |[Link](/2016/README.md) |
+|2017  |1-13 | - | [Link](/2016/) |[Link](/2016/README.md) |
 
 ## To run ##