Problem p00822 (C++) — buggy submission, verdict: Memory Limit Exceeded

#include <algorithm>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

using namespace std;

#define FOR(i, k, n) for (int i = (k); i < (int)(n); ++i)
#define REP(i, n) FOR(i, 0, n)
#define FORIT(i, c)                                                            \\
  for (__typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)

template <class T> void debug(T begin, T end) {
  for (T i = begin; i != end; ++i)
    cerr << *i << " ";
  cerr << endl;
}
inline bool valid(int x, int y, int W, int H) {
  return (x >= 0 && y >= 0 && x < W && y < H);
}

typedef long long ll;
const int INF = 100000000;
const double EPS = 1e-8;
const int MOD = 1000000007;
int dx[9] = {1, 0, -1, 0, 0, 0, 2, -2, 0};
int dy[9] = {0, 1, 0, -1, 0, 2, 0, 0, -2};

int main() {
  int D;
  int sch[365][4][4] = {};
  while (cin >> D && D) {
    bool goal = false;
    REP(i, D) REP(y, 4) REP(x, 4) cin >> sch[i][y][x];
    static bool used[366][16][2401];
    memset(used, 0, sizeof(used));
    queue<int> qd, qy, qx;
    queue<vector<int>> qv;
    vector<int> s(4, 0);
    qd.push(0);
    qx.push(1);
    qy.push(1);
    qv.push(s);
    while (!qd.empty()) {
      int d = qd.front();
      qd.pop();
      int x = qx.front();
      qx.pop();
      int y = qy.front();
      qy.pop();
      // printf("d = %d x = %d y = %d\\n", d, x, y);
      vector<int> v = qv.front();
      qv.pop();
      if (d == D) {
        goal = true;
        break;
      }
      REP(i, 4) v[i]++;
      bool ok = true;
      REP(dy, 2) REP(dx, 2) if (sch[d][y + dy][x + dx] == 1) ok = false;
      if (x == 0 && y == 0)
        v[0] = 0;
      if (x == 2 && y == 0)
        v[1] = 0;
      if (x == 0 && y == 2)
        v[2] = 0;
      if (x == 2 && y == 2)
        v[3] = 0;
      REP(i, 4) if (v[i] >= 7) ok = false;
      if (!ok)
        continue;
      REP(r, 9) {
        bool ok2 = true;
        int nx = x + dx[r];
        int ny = y + dy[r];
        REP(dx, 2) REP(dy, 2) ok2 &= valid(nx + dx, ny + dy, 4, 4);
        if (!ok2)
          continue;
        if (used[d + 1][ny + nx * 4][v[0] + 7 * v[1] + 49 * v[2] + 343 * v[3]])
          continue;
        used[d + 1][ny + nx * 4][v[0] + 7 * v[1] + 49 * v[2] + 343 * v[3]] =
            true;
        qd.push(d + 1);
        qx.push(nx);
        qy.push(ny);
        qv.push(v);
      }
    }
    if (goal)
      cout << 1 << endl;
    else
      cout << 0 << endl;
  }
  return 0;
}

Error: MLE

Fixed submission:

#include <algorithm>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

using namespace std;

#define FOR(i, k, n) for (int i = (k); i < (int)(n); ++i)
#define REP(i, n) FOR(i, 0, n)
#define FORIT(i, c)                                                            \\
  for (__typeof((c).begin()) i = (c).begin(); i != (c).end(); ++i)

template <class T> void debug(T begin, T end) {
  for (T i = begin; i != end; ++i)
    cerr << *i << " ";
  cerr << endl;
}
inline bool valid(int x, int y, int W, int H) {
  return (x >= 0 && y >= 0 && x < W && y < H);
}

typedef long long ll;
const int INF = 100000000;
const double EPS = 1e-8;
const int MOD = 1000000007;
int dx[9] = {1, 0, -1, 0, 0, 0, 2, -2, 0};
int dy[9] = {0, 1, 0, -1, 0, 2, 0, 0, -2};

int main() {
  int D;
  int sch[365][4][4] = {};
  while (cin >> D && D) {
    bool goal = false;
    REP(i, D) REP(y, 4) REP(x, 4) cin >> sch[i][y][x];
    static bool used[366][16][2401];
    memset(used, 0, sizeof(used));
    queue<int> qd, qy, qx;
    queue<vector<int>> qv;
    vector<int> s(4, 0);
    qd.push(0);
    qx.push(1);
    qy.push(1);
    qv.push(s);
    while (!qd.empty()) {
      int d = qd.front();
      qd.pop();
      int x = qx.front();
      qx.pop();
      int y = qy.front();
      qy.pop();
      // printf("d = %d x = %d y = %d\\n", d, x, y);
      vector<int> v = qv.front();
      qv.pop();
      if (d == D) {
        goal = true;
        break;
      }
      REP(i, 4) v[i]++;
      bool ok = true;
      REP(dy, 2) REP(dx, 2) if (sch[d][y + dy][x + dx] == 1) ok = false;
      if (x == 0 && y == 0)
        v[0] = 0;
      if (x == 2 && y == 0)
        v[1] = 0;
      if (x == 0 && y == 2)
        v[2] = 0;
      if (x == 2 && y == 2)
        v[3] = 0;
      REP(i, 4) if (v[i] >= 7) ok = false;
      if (!ok)
        continue;
      REP(r, 9) {
        bool ok2 = true;
        int nx = x + dx[r];
        int ny = y + dy[r];
        REP(dx, 2) REP(dy, 2) ok2 &= valid(nx + dx, ny + dy, 4, 4);
        if (!ok2)
          continue;
        if (used[d + 1][ny + nx * 4][v[0] + 7 * v[1] + 49 * v[2] + 343 * v[3]])
          continue;
        qd.push(d + 1);
        qx.push(nx);
        qy.push(ny);
        qv.push(v);
      }
    }
    if (goal)
      cout << 1 << endl;
    else
      cout << 0 << endl;
  }
  return 0;
}