Problem p01478 (C++) — buggy submission, verdict: Memory Limit Exceeded

#include <algorithm> // other
#include <bitset>
#include <cassert> // c
#include <complex>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream> // io
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <regex>
#include <set>
#include <sstream>
#include <stack>
#include <vector> // container
using namespace std;

typedef long long ll;

#define ALL(c) (begin(c)), (end(c))
#define REP(i, n) FOR(i, 0, n)
#define REPr(i, n) FORr(i, 0, n)
#define FOR(i, l, r) for (int i = (int)(l); i < (int)(r); ++i)
#define FORr(i, l, r) for (int i = (int)(r)-1; i >= (int)(l); --i)
#define EACH(it, o) for (auto it = (o).begin(); it != (o).end(); ++it)
#define IN(l, v, r) ((l) <= (v) && (v) < (r))
#define UNIQUE(v) v.erase(unique(ALL(v)), v.end())
// debug
#define DUMP(x) cerr << #x << " = " << (x)
#define LINE() cerr << " (L" << __LINE__ << ")"

class range {
private:
  struct Iter {
    int v;
    int operator*() { return v; }
    bool operator!=(Iter &itr) { return v < itr.v; }
    void operator++() { ++v; }
  };
  Iter i, n;

public:
  range(int n) : i({0}), n({n}) {}
  range(int i, int n) : i({i}), n({n}) {}
  Iter &begin() { return i; }
  Iter &end() { return n; }
};

// output
template <typename T> ostream &operator<<(ostream &os, const vector<T> &as) {
  REP(i, as.size()) {
    if (i != 0)
      os << " ";
    os << as[i];
  }
  return os;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<vector<T>> &as) {
  REP(i, as.size()) {
    if (i != 0)
      os << endl;
    os << as[i];
  }
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &ss) {
  for (auto a : ss) {
    if (a != ss.begin())
      os << " ";
    os << a;
  }
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}
template <typename K, typename V>
ostream &operator<<(ostream &os, const map<K, V> &m) {
  bool isF = true;
  for (auto &p : m) {
    if (!isF)
      os << endl;
    os << p;
    isF = false;
  }
  return os;
}
template <typename T1> ostream &operator<<(ostream &os, const tuple<T1> &t) {
  os << get<0>(t);
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const tuple<T1, T2> &t) {
  os << get<0>(t) << " " << get<1>(t);
  return os;
}
template <typename T1, typename T2, typename T3>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5, T6> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t) << " " << get<5>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6, typename T7>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5, T6, T7> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t) << " " << get<5>(t) << " " << get<6>(t);
  return os;
}

// input
char tmp[1000];
#define nextInt(n) scanf("%d", &n)
#define nextLong(n) scanf("%lld", &n) // I64d
#define nextDouble(n) scanf("%lf", &n)
#define nextChar(n) scanf("%c", &n)
#define nextString(n)                                                          \\
  scanf("%s", tmp);                                                            \\
  n = tmp

// values
template <typename T> T INF() { assert(false); };
template <> int INF<int>() { return 1 << 28; };
template <> ll INF<ll>() { return 1LL << 58; };
template <> float INF<float>() { return 1e10; };
template <> double INF<double>() { return 1e16; };
template <> long double INF<long double>() { return 1e16; };

template <class T> T EPS() { assert(false); };
template <> int EPS<int>() { return 1; };
template <> ll EPS<ll>() { return 1LL; };
template <> float EPS<float>() { return 1e-8; };
template <> double EPS<double>() { return 1e-8; };
template <> long double EPS<long double>() { return 1e-8; };

template <typename T, typename U> T pmod(T v, U M) { return (v % M + M) % M; }

namespace EGraph {
typedef ll Cost;
Cost CINF = INF<Cost>();
struct Edge {
  int from, to;
  Cost cost;
  Edge(int from, int to, Cost cost) : from(from), to(to), cost(cost){};
  bool operator<(Edge r) const { return cost < r.cost; }
  bool operator>(Edge r) const { return cost > r.cost; }
};
typedef vector<vector<Edge>> Graph;
} // namespace EGraph
using namespace EGraph;

namespace ShortestPath {
using namespace EGraph;

struct Task {
  int prev, pos;
  Cost cost;
  Task(int prev, int pos, Cost cost) : prev(prev), pos(pos), cost(cost){};
  bool operator>(const Task &r) const { return cost > r.cost; }
};

// verified by codoforces 144D
// http://codeforces.com/contest/144/submission/4976825
//  // 負の辺がない
//  // O(E*logV)
vector<Cost> dijkstra(const Graph &g, const int s, vector<int> &prev) {
  const int V = g.size();
  vector<Cost> d(V, CINF);
  d[s] = 0;
  fill(ALL(prev), -2);

  priority_queue<Task, vector<Task>, greater<Task>> que;
  que.push(Task(-1, s, 0)); // [ ,e,,f, ] <=> e.cost < e.cost
  vector<bool> visited(V);
  while (!que.empty()) {
    Task task = que.top();
    que.pop();
    if (visited[task.pos])
      continue;
    visited[task.pos] = true;
    prev[task.pos] = task.prev;
    EACH(e, g[task.pos]) if (d[e->to] > d[e->from] + e->cost) {
      d[e->to] = d[e->from] + e->cost;
      que.push(Task(e->from, e->to, d[e->to]));
    }
  }
  return d;
}
vector<Cost> dijkstra(const Graph &g, const int s) {
  vector<int> prev(g.size());
  return dijkstra(g, s, prev);
}
} // namespace ShortestPath
using namespace ShortestPath;

class Main {
public:
  int N;
  vector<vector<int>> cs;

  map<vector<short>, int> enc;
  // map<int,vector<int>> dec;

  void run() {
    cin >> N;
    cs = vector<vector<int>>(N, vector<int>(N));
    REP(y, N) REP(x, N) cin >> cs[y][x];

    vector<short> per(N);
    iota(ALL(per), 0);
    int ind = 0;
    do {
      enc[per] = ind;
      // dec[ind]=per;
      int te = 0;
      REP(i, N) for (int j = i + 1; j < N; j++) if (per[i] > per[j]) te++;
      ind++;
    } while (next_permutation(ALL(per)));

    Graph g(ind);
    int code = 0;
    iota(ALL(per), 0);
    do {
      REP(i, N) for (int j = i + 1; j < N; j++) {
        swap(per[i], per[j]);
        int ncode = enc[per];
        g[code].push_back(Edge(code, ncode, cs[per[i]][per[j]]));
        swap(per[i], per[j]);
      }
      code++;
    } while (next_permutation(ALL(per)));

    vector<Cost> ds = dijkstra(g, 0);
    ll Mv = 0;
    REP(code, ind) Mv = max(Mv, ds[code]);
    cout << Mv << endl;
  }
};

int main() {
  cout << fixed << setprecision(20);
  cin.tie(0);
  ios::sync_with_stdio(false);
  Main().run();
  return 0;
}

Error: MLE

Fixed submission:

#include <algorithm> // other
#include <bitset>
#include <cassert> // c
#include <complex>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream> // io
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <regex>
#include <set>
#include <sstream>
#include <stack>
#include <vector> // container
using namespace std;

typedef long long ll;

#define ALL(c) (begin(c)), (end(c))
#define REP(i, n) FOR(i, 0, n)
#define REPr(i, n) FORr(i, 0, n)
#define FOR(i, l, r) for (int i = (int)(l); i < (int)(r); ++i)
#define FORr(i, l, r) for (int i = (int)(r)-1; i >= (int)(l); --i)
#define EACH(it, o) for (auto it = (o).begin(); it != (o).end(); ++it)
#define IN(l, v, r) ((l) <= (v) && (v) < (r))
#define UNIQUE(v) v.erase(unique(ALL(v)), v.end())
// debug
#define DUMP(x) cerr << #x << " = " << (x)
#define LINE() cerr << " (L" << __LINE__ << ")"

class range {
private:
  struct Iter {
    int v;
    int operator*() { return v; }
    bool operator!=(Iter &itr) { return v < itr.v; }
    void operator++() { ++v; }
  };
  Iter i, n;

public:
  range(int n) : i({0}), n({n}) {}
  range(int i, int n) : i({i}), n({n}) {}
  Iter &begin() { return i; }
  Iter &end() { return n; }
};

// output
template <typename T> ostream &operator<<(ostream &os, const vector<T> &as) {
  REP(i, as.size()) {
    if (i != 0)
      os << " ";
    os << as[i];
  }
  return os;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<vector<T>> &as) {
  REP(i, as.size()) {
    if (i != 0)
      os << endl;
    os << as[i];
  }
  return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &ss) {
  for (auto a : ss) {
    if (a != ss.begin())
      os << " ";
    os << a;
  }
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}
template <typename K, typename V>
ostream &operator<<(ostream &os, const map<K, V> &m) {
  bool isF = true;
  for (auto &p : m) {
    if (!isF)
      os << endl;
    os << p;
    isF = false;
  }
  return os;
}
template <typename T1> ostream &operator<<(ostream &os, const tuple<T1> &t) {
  os << get<0>(t);
  return os;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const tuple<T1, T2> &t) {
  os << get<0>(t) << " " << get<1>(t);
  return os;
}
template <typename T1, typename T2, typename T3>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5, T6> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t) << " " << get<5>(t);
  return os;
}
template <typename T1, typename T2, typename T3, typename T4, typename T5,
          typename T6, typename T7>
ostream &operator<<(ostream &os, const tuple<T1, T2, T3, T4, T5, T6, T7> &t) {
  os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t) << " " << get<3>(t)
     << " " << get<4>(t) << " " << get<5>(t) << " " << get<6>(t);
  return os;
}

// input
char tmp[1000];
#define nextInt(n) scanf("%d", &n)
#define nextLong(n) scanf("%lld", &n) // I64d
#define nextDouble(n) scanf("%lf", &n)
#define nextChar(n) scanf("%c", &n)
#define nextString(n)                                                          \\
  scanf("%s", tmp);                                                            \\
  n = tmp

// values
template <typename T> T INF() { assert(false); };
template <> int INF<int>() { return 1 << 28; };
template <> ll INF<ll>() { return 1LL << 58; };
template <> float INF<float>() { return 1e10; };
template <> double INF<double>() { return 1e16; };
template <> long double INF<long double>() { return 1e16; };

template <class T> T EPS() { assert(false); };
template <> int EPS<int>() { return 1; };
template <> ll EPS<ll>() { return 1LL; };
template <> float EPS<float>() { return 1e-8; };
template <> double EPS<double>() { return 1e-8; };
template <> long double EPS<long double>() { return 1e-8; };

template <typename T, typename U> T pmod(T v, U M) { return (v % M + M) % M; }

namespace EGraph {
typedef ll Cost;
Cost CINF = INF<Cost>();
struct Edge {
  int from, to;
  Cost cost;
  Edge(int from, int to, Cost cost) : from(from), to(to), cost(cost){};
  bool operator<(Edge r) const { return cost < r.cost; }
  bool operator>(Edge r) const { return cost > r.cost; }
};
typedef vector<vector<Edge>> Graph;
} // namespace EGraph
using namespace EGraph;

namespace ShortestPath {
using namespace EGraph;

struct Task {
  int prev, pos;
  Cost cost;
  Task(int prev, int pos, Cost cost) : prev(prev), pos(pos), cost(cost){};
  bool operator>(const Task &r) const { return cost > r.cost; }
};

// verified by codoforces 144D
// http://codeforces.com/contest/144/submission/4976825
//  // 負の辺がない
//  // O(E*logV)
vector<Cost> dijkstra(const Graph &g, const int s, vector<int> &prev) {
  const int V = g.size();
  vector<Cost> d(V, CINF);
  d[s] = 0;
  fill(ALL(prev), -2);

  priority_queue<Task, vector<Task>, greater<Task>> que;
  que.push(Task(-1, s, 0)); // [ ,e,,f, ] <=> e.cost < e.cost
  vector<bool> visited(V);
  while (!que.empty()) {
    Task task = que.top();
    que.pop();
    if (visited[task.pos])
      continue;
    visited[task.pos] = true;
    prev[task.pos] = task.prev;
    EACH(e, g[task.pos]) if (d[e->to] > d[e->from] + e->cost) {
      d[e->to] = d[e->from] + e->cost;
      que.push(Task(e->from, e->to, d[e->to]));
    }
  }
  return d;
}
vector<Cost> dijkstra(const Graph &g, const int s) {
  vector<int> prev(g.size());
  return dijkstra(g, s, prev);
}
} // namespace ShortestPath
using namespace ShortestPath;

class Main {
public:
  int N;
  vector<vector<int>> cs;

  map<vector<int>, int> enc;
  map<int, vector<int>> dec;
  map<int, int> tenti;

  void run() {
    cin >> N;
    cs = vector<vector<int>>(N, vector<int>(N));
    REP(y, N) REP(x, N) cin >> cs[y][x];

    vector<int> per(N);
    iota(ALL(per), 0);
    int ind = 0;
    do {
      enc[per] = ind;
      dec[ind] = per;
      int te = 0;
      REP(i, N) for (int j = i + 1; j < N; j++) if (per[i] > per[j]) te++;
      tenti[ind] = te;
      ind++;
    } while (next_permutation(ALL(per)));

    Graph g(ind);
    REP(i, N) REP(code, ind) {
      vector<int> as = dec[code];
      REP(i, N) for (int j = i + 1; j < N; j++) {
        swap(as[i], as[j]);
        int ncode = enc[as];
        g[code].push_back(Edge(code, ncode, cs[as[i]][as[j]]));
        swap(as[i], as[j]);
      }
    }
    vector<Cost> ds = dijkstra(g, 0);
    ll Mv = 0;
    REP(code, ind) Mv = max(Mv, ds[code]);
    cout << Mv << endl;
  }
};

int main() {
  cout << fixed << setprecision(20);
  cin.tie(0);
  ios::sync_with_stdio(false);
  Main().run();
  return 0;
}