Merge pull request #409 from david-ds/skasch/day22

Day 22, C++

Author: skasch

day-22/input/skasch.txt

@@ -0,0 +1,53 @@
+Player 1:
+7
+1
+9
+10
+12
+4
+38
+22
+18
+3
+27
+31
+43
+33
+47
+42
+21
+24
+50
+39
+8
+6
+16
+46
+11
+
+Player 2:
+49
+41
+40
+35
+44
+29
+30
+19
+14
+2
+34
+17
+25
+5
+15
+32
+20
+48
+45
+26
+37
+28
+36
+23
+13

day-22/part-1/skasch.cpp

@@ -0,0 +1,65 @@
+#include <ctime>
+#include <deque>
+#include <iostream>
+#include <sstream>
+#include <string>
+
+static std::deque<int> kPlayer1;
+static std::deque<int> kPlayer2;
+
+std::deque<int> *Play() {
+  int card1 = kPlayer1.front();
+  kPlayer1.pop_front();
+  int card2 = kPlayer2.front();
+  kPlayer2.pop_front();
+  if (card1 > card2) {
+    kPlayer1.push_back(card1);
+    kPlayer1.push_back(card2);
+    return kPlayer2.empty() ? &kPlayer1 : nullptr;
+  } else {
+    kPlayer2.push_back(card2);
+    kPlayer2.push_back(card1);
+    return kPlayer1.empty() ? &kPlayer2 : nullptr;
+  }
+}
+
+std::string run(const std::string &input) {
+  // Your code goes here
+  std::istringstream iss(input);
+  std::string line;
+  std::getline(iss, line);
+  for (; std::getline(iss, line);) {
+    if (line.empty()) {
+      break;
+    }
+    kPlayer1.push_back(atoi(line.c_str()));
+  }
+  std::getline(iss, line);
+  for (; std::getline(iss, line);) {
+    kPlayer2.push_back(atoi(line.c_str()));
+  }
+  std::deque<int> *winner = nullptr;
+  while (winner == nullptr) {
+    winner = Play();
+  }
+  int result = 0;
+  for (int index = 0; index < winner->size(); ++index) {
+    result += (winner->size() - index) * winner->at(index);
+  }
+  return std::to_string(result);
+}
+
+int main(int argc, char **argv) {
+  if (argc < 2) {
+    std::cout << "Missing one argument" << std::endl;
+    exit(1);
+  }
+
+  clock_t start = clock();
+  auto answer = run(argv[1]);
+
+  std::cout << "_duration:" << float(clock() - start) * 1000.0 / CLOCKS_PER_SEC
+            << "\n";
+  std::cout << answer << "\n";
+  return 0;
+}

day-22/part-2/skasch.cpp

@@ -0,0 +1,111 @@
+#include <ctime>
+#include <deque>
+#include <iostream>
+#include <iterator>
+#include <sstream>
+#include <string>
+#include <unordered_set>
+
+std::string ToString(const std::deque<int> &player1,
+                     const std::deque<int> &player2) {
+  std::string s;
+  for (int card1 : player1) {
+    s.push_back(card1);
+  }
+  s.push_back('_');
+  for (int card2 : player2) {
+    s.push_back(card2);
+  }
+  return s;
+}
+
+std::deque<int> *Play(std::deque<int> &player1, std::deque<int> &player2,
+                      std::unordered_set<std::string> &visited);
+
+std::deque<int> *Game(std::deque<int> &player1, std::deque<int> &player2) {
+  std::unordered_set<std::string> visited;
+  std::deque<int> *winner = nullptr;
+  while (winner == nullptr) {
+    winner = Play(player1, player2, visited);
+  }
+  return winner;
+}
+
+std::deque<int> *Play(std::deque<int> &player1, std::deque<int> &player2,
+                      std::unordered_set<std::string> &visited) {
+  std::string s = ToString(player1, player2);
+  if (auto it = visited.find(s); it != visited.end()) {
+    return &player1;
+  }
+  visited.insert(s);
+  int card1 = player1.front();
+  player1.pop_front();
+  int card2 = player2.front();
+  player2.pop_front();
+  bool player1_wins = card1 > card2;
+  if (card1 <= player1.size() && card2 <= player2.size()) {
+    std::deque<int> sub_player1;
+    auto sub_card1 = player1.begin();
+    for (int idx = 0; idx < card1; ++idx) {
+      sub_player1.push_back(*sub_card1);
+      std::advance(sub_card1, 1);
+    }
+    std::deque<int> sub_player2;
+    auto sub_card2 = player2.begin();
+    for (int idx = 0; idx < card2; ++idx) {
+      sub_player2.push_back(*sub_card2);
+      std::advance(sub_card2, 1);
+    }
+    std::deque<int> *winner = Game(sub_player1, sub_player2);
+    player1_wins = winner == &sub_player1;
+  }
+  if (player1_wins) {
+    player1.push_back(card1);
+    player1.push_back(card2);
+    return player2.empty() ? &player1 : nullptr;
+  } else {
+    player2.push_back(card2);
+    player2.push_back(card1);
+    return player1.empty() ? &player2 : nullptr;
+  }
+}
+
+std::string run(const std::string &input) {
+  // Your code goes here
+  std::istringstream iss(input);
+  std::string line;
+  std::getline(iss, line);
+  std::deque<int> player1;
+  std::deque<int> player2;
+  for (; std::getline(iss, line);) {
+    if (line.empty()) {
+      break;
+    }
+    player1.push_back(atoi(line.c_str()));
+  }
+  std::getline(iss, line);
+  for (; std::getline(iss, line);) {
+    player2.push_back(atoi(line.c_str()));
+  }
+  std::deque<int> *winner = Game(player1, player2);
+  int result = 0;
+  for (int index = 0; index < winner->size(); ++index) {
+    result += (winner->size() - index) * winner->at(index);
+  }
+  return std::to_string(result);
+}
+
+int main(int argc, char **argv) {
+  if (argc < 2) {
+    std::cout << "Missing one argument" << std::endl;
+    exit(1);
+  }
+
+  clock_t start = clock();
+  auto answer = run(argv[1]);
+
+  std::cout << "_duration:" << float(clock() - start) * 1000.0 / CLOCKS_PER_SEC
+            << "\n";
+  std::cout << answer << "\n";
+  return 0;
+}