一个关于麻将清一色的问题？ 第1页

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       #include <bits/stdc++.h> using namespace std;  constexpr bool kAllowPureEmptyWait = true;  class ScopedInc {  public:   explicit ScopedInc(unsigned char& c, int v = 1) : c_(c), v_(v) { c += v; }   ~ScopedInc() { c_ -= v_; }  private:   unsigned char& c_;   int v_; };  class Hand {  public:   explicit Hand(int i) {     num_tiles_ = 0;     for (auto& v : tiles_) {       num_tiles_ += v = i % 5;       i /= 5;     }   }    int num_tiles() const { return num_tiles_; }    bool is_waiting() {     for (auto& v : tiles_) {       if (!kAllowPureEmptyWait && v == 4) continue;       ScopedInc s(v);       if (is_winning()) return true;     }     return false;   }      void print() const {     for (int i = 0; i < tiles_.size(); i++) {       for (int j = 0; j < tiles_[i]; j++) {         cout << i + 1;       }     }   }      vector<int> get_successors() {     vector<int> ret;     for (auto& v : tiles_) {       if (v == 4) continue;       ScopedInc s(v);       ret.push_back(encode());     }     return ret;   }   private:   using Arr = array<unsigned char, 9>;   using It = Arr::iterator;    bool is_winning() {     // Pair     for (auto& v : tiles_) {       if (v < 2) continue;       ScopedInc s(v, -2);       if (is_winning_without_pair(/*num_groups=*/0, tiles_.begin())) return true;     }     return false;   }      bool is_winning_without_pair(int num_groups, It start) {     if (num_groups == 4) return true;     for (It i = start; i != tiles_.end(); ++i) {       // Identical group       if (*i >= 3) {         ScopedInc s(*i, -3);         if (is_winning_without_pair(num_groups + 1, i)) return true;       }       // Sequential group       if (tiles_.end() - i >= 3 && i[0] > 0 && i[1] > 0 && i[2] > 0) {         ScopedInc s0(i[0], -1), s1(i[1], -1), s2(i[2], -1);         if (is_winning_without_pair(num_groups + 1, i)) return true;       }     }     return false;   }    int encode() const {     int ret = 0;     for (auto v : tiles_ | views::reverse) {       ret = ret * 5 + v;     }     return ret;   }      Arr tiles_;   int num_tiles_; };  int main() {   constexpr int N = 5*5*5*5*5*5*5*5*5;   queue<int> q;   vector<int> failure_source(N);   for (int i = 0; i < N; i++) {     Hand hand(i);     if (hand.num_tiles() == 13 && !hand.is_waiting()) {       q.push(i);       failure_source[i] = i;     }   }   vector<bool> ok(N, true);   while (!q.empty()) {     Hand hand(q.front());     for (int successor : hand.get_successors()) {       if (ok[successor]) {         q.push(successor);         ok[successor] = false;         failure_source[successor] = failure_source[q.front()];       }     }     q.pop();   }   int best_hand_v = -1, max_tiles = 0;   for (int i = 0; i < N; i++) {     int num_tiles = Hand(i).num_tiles();     if (num_tiles < 13) continue;     if (ok[i] && num_tiles > max_tiles) {       best_hand_v = i;       max_tiles = num_tiles;     }   }   cout << "Best max tiles: " << max_tiles << endl;   map<int, int> counts;   for (int i = 0; i < N; i++) {     Hand hand(i);     int num_tiles = hand.num_tiles();     if (num_tiles < 13 || !ok[i]) continue;     ++counts[num_tiles];     if (num_tiles == max_tiles) {       hand.print();       cout << endl;     }   }   cout << "# of solutions by # of tiles: " << endl;   for (auto [num_tiles, count] : counts) {     cout << num_tiles << ": " << count << endl;   }      return 0; }