Problem p01511 (C++) — buggy submission, verdict: Time Limit Exceeded

#include "bits/stdc++.h"
#include <unordered_map>
#include <unordered_set>
#pragma warning(disable : 4996)
using namespace std;
using ld = long double;
const ld eps = 1e-9;

const int mod = 1000000009;
struct Mod {
public:
  int num;
  Mod() : Mod(0) { ; }
  Mod(long long int n) : num((n % mod + mod) % mod) {
    static_assert(mod < INT_MAX / 2,
                  "mod is too big, please make num 'long long int' from 'int'");
  }
  Mod(int n) : Mod(static_cast<long long int>(n)) { ; }
  operator int() { return num; }
};

Mod operator+(const Mod a, const Mod b) { return Mod((a.num + b.num) % mod); }
Mod operator+(const long long int a, const Mod b) { return Mod(a) + b; }
Mod operator+(const Mod a, const long long int b) { return b + a; }
Mod operator++(Mod &a) { return a + Mod(1); }
Mod operator-(const Mod a, const Mod b) {
  return Mod((mod + a.num - b.num) % mod);
}
Mod operator-(const long long int a, const Mod b) { return Mod(a) - b; }
Mod operator--(Mod &a) { return a - Mod(1); }
Mod operator*(const Mod a, const Mod b) {
  return Mod(((long long)a.num * b.num) % mod);
}
Mod operator*(const long long int a, const Mod b) { return Mod(a) * b; }
Mod operator*(const Mod a, const long long int b) { return Mod(b) * a; }
Mod operator*(const Mod a, const int b) { return Mod(b) * a; }
Mod operator+=(Mod &a, const Mod b) { return a = a + b; }
Mod operator+=(long long int &a, const Mod b) { return a = a + b; }
Mod operator-=(Mod &a, const Mod b) { return a = a - b; }
Mod operator-=(long long int &a, const Mod b) { return a = a - b; }
Mod operator*=(Mod &a, const Mod b) { return a = a * b; }
Mod operator*=(long long int &a, const Mod b) { return a = a * b; }
Mod operator*=(Mod &a, const long long int &b) { return a = a * b; }
Mod operator^(const Mod a, const int n) {
  if (n == 0)
    return Mod(1);
  Mod res = (a * a) ^ (n / 2);
  if (n % 2)
    res = res * a;
  return res;
}
Mod mod_pow(const Mod a, const long long int n) {
  if (n == 0)
    return Mod(1);
  Mod res = mod_pow((a * a), (n / 2));
  if (n % 2)
    res = res * a;
  return res;
}
Mod inv(const Mod a) { return a ^ (mod - 2); }
Mod operator/(const Mod a, const Mod b) {
  assert(b.num != 0);
  return a * inv(b);
}
Mod operator/(const long long int a, const Mod b) { return Mod(a) / b; }
Mod operator/=(Mod &a, const Mod b) { return a = a / b; }

#define MAX_MOD_N 1024000

Mod fact[MAX_MOD_N], factinv[MAX_MOD_N];
void init(const int amax = MAX_MOD_N) {
  fact[0] = Mod(1);
  factinv[0] = 1;
  for (int i = 0; i < amax - 1; ++i) {
    fact[i + 1] = fact[i] * Mod(i + 1);
    factinv[i + 1] = factinv[i] / Mod(i + 1);
  }
}
Mod comb(const int a, const int b) {
  return fact[a] * factinv[b] * factinv[a - b];
}

template <typename T>
vector<vector<T>> keisann(const vector<vector<T>> l,
                          const vector<vector<T>> r) {
  vector<vector<T>> ans(l.size(), vector<T>(r[0].size()));
  assert(l[0].size() == r.size());
  for (unsigned int h = 0; h < l.size(); ++h) {
    for (unsigned int i = 0; i < r.size(); ++i) {
      for (unsigned int w = 0; w < r[0].size(); ++w) {

        ans[h][w] += l[h][i] * r[i][w];
      }
    }
  }
  return ans;
}

template <typename T>
vector<vector<T>> powgyou(vector<vector<T>> a, const long long int n) {
  assert(a.size() == a[0].size());
  if (!n) {
    vector<vector<T>> e(a.size(), vector<T>(a[0].size()));
    for (unsigned int i = 0; i < a.size(); ++i) {
      e[i][i] = 1;
    }
    return e;
  }
  if (n == 1)
    return a;
  else {
    vector<vector<T>> ans(a.size(), vector<T>(a[0].size(), 0));
    ans = powgyou(a, n / 2);
    ans = keisann(ans, ans);
    if (n % 2) {
      ans = keisann(ans, a);
    }
    return ans;
  }
}

int main() {
  int casenum = 0;
  while (1) {
    casenum++;
    int W, N;
    long long int H;
    cin >> W >> H >> N;
    if (!W)
      break;
    map<long long int, vector<int>> mp;
    vector<vector<Mod>> forspaces(W, vector<Mod>(W));
    for (int y = 0; y < W; ++y) {
      for (int x = 0; x < W; ++x) {
        if (abs(x - y) <= 1)
          forspaces[y][x] = true;
      }
    }
    bool flag = true;
    for (int i = 0; i < N; ++i) {
      int x;
      long long y;
      cin >> x >> y;
      x--;
      y--;
      if (!x && !y) {
        flag = false;
      }
      mp[y].push_back(x);
    }
    Mod ans = 0;
    if (flag) {
      for (int i = 0; i < W - 1; ++i) {
        mp[H - 1].push_back(i);
      }
      vector<vector<Mod>> nums(W, vector<Mod>(1));
      nums[0][0] = 1;
      long long int nowy = 0;
      for (auto it = mp.begin(); it != mp.end(); ++it) {
        long long int nexty = it->first;
        vector<int> obs(it->second);
        if (nexty == nowy)
          continue;
        else {
          long long int spaces = nexty - nowy - 1;
          nums = keisann(powgyou(forspaces, spaces), nums);

          vector<vector<Mod>> forobs(forspaces);
          for (int y = 0; y < W; ++y) {
            for (int x = 0; x < W; ++x) {
              if (find(obs.begin(), obs.end(), y) != obs.end())
                forobs[y][x] = false;
            }
          }
          nums = keisann(forobs, nums);
          nowy = nexty;
        }
      }
      ans = nums[W - 1][0];
    }

    cout << "Case " << casenum << ": " << ans.num << endl;
  }
  return 0;
}

Error: TLE

Fixed submission:

#include "bits/stdc++.h"
#include <unordered_map>
#include <unordered_set>
#pragma warning(disable : 4996)
using namespace std;
using ld = long double;
const ld eps = 1e-9;

const int mod = 1000000009;
struct Mod {
public:
  int num;
  Mod() : Mod(0) { ; }
  Mod(long long int n) : num((n % mod + mod) % mod) {
    static_assert(mod < INT_MAX / 2,
                  "mod is too big, please make num 'long long int' from 'int'");
  }
  Mod(int n) : Mod(static_cast<long long int>(n)) { ; }
  operator int() { return num; }
};

Mod operator+(const Mod a, const Mod b) { return Mod((a.num + b.num) % mod); }
Mod operator+(const long long int a, const Mod b) { return Mod(a) + b; }
Mod operator+(const Mod a, const long long int b) { return b + a; }
Mod operator++(Mod &a) { return a + Mod(1); }
Mod operator-(const Mod a, const Mod b) {
  return Mod((mod + a.num - b.num) % mod);
}
Mod operator-(const long long int a, const Mod b) { return Mod(a) - b; }
Mod operator--(Mod &a) { return a - Mod(1); }
Mod operator*(const Mod a, const Mod b) {
  return Mod(((long long)a.num * b.num) % mod);
}
Mod operator*(const long long int a, const Mod b) { return Mod(a) * b; }
Mod operator*(const Mod a, const long long int b) { return Mod(b) * a; }
Mod operator*(const Mod a, const int b) { return Mod(b) * a; }
Mod operator+=(Mod &a, const Mod b) { return a = a + b; }
Mod operator+=(long long int &a, const Mod b) { return a = a + b; }
Mod operator-=(Mod &a, const Mod b) { return a = a - b; }
Mod operator-=(long long int &a, const Mod b) { return a = a - b; }
Mod operator*=(Mod &a, const Mod b) { return a = a * b; }
Mod operator*=(long long int &a, const Mod b) { return a = a * b; }
Mod operator*=(Mod &a, const long long int &b) { return a = a * b; }
Mod operator^(const Mod a, const int n) {
  if (n == 0)
    return Mod(1);
  Mod res = (a * a) ^ (n / 2);
  if (n % 2)
    res = res * a;
  return res;
}
Mod mod_pow(const Mod a, const long long int n) {
  if (n == 0)
    return Mod(1);
  Mod res = mod_pow((a * a), (n / 2));
  if (n % 2)
    res = res * a;
  return res;
}
Mod inv(const Mod a) { return a ^ (mod - 2); }
Mod operator/(const Mod a, const Mod b) {
  assert(b.num != 0);
  return a * inv(b);
}
Mod operator/(const long long int a, const Mod b) { return Mod(a) / b; }
Mod operator/=(Mod &a, const Mod b) { return a = a / b; }

#define MAX_MOD_N 1024000

Mod fact[MAX_MOD_N], factinv[MAX_MOD_N];
void init(const int amax = MAX_MOD_N) {
  fact[0] = Mod(1);
  factinv[0] = 1;
  for (int i = 0; i < amax - 1; ++i) {
    fact[i + 1] = fact[i] * Mod(i + 1);
    factinv[i + 1] = factinv[i] / Mod(i + 1);
  }
}
Mod comb(const int a, const int b) {
  return fact[a] * factinv[b] * factinv[a - b];
}

template <typename T>
vector<vector<T>> keisann(const vector<vector<T>> l,
                          const vector<vector<T>> r) {
  vector<vector<T>> ans(l.size(), vector<T>(r[0].size()));
  assert(l[0].size() == r.size());
  for (unsigned int h = 0; h < l.size(); ++h) {
    for (unsigned int i = 0; i < r.size(); ++i) {
      for (unsigned int w = 0; w < r[0].size(); ++w) {

        ans[h][w] += l[h][i] * r[i][w];
      }
    }
  }
  return ans;
}

template <typename T>
vector<vector<T>> powgyou(vector<vector<T>> a, const long long int n) {
  assert(a.size() == a[0].size());
  if (!n) {
    vector<vector<T>> e(a.size(), vector<T>(a[0].size()));
    for (unsigned int i = 0; i < a.size(); ++i) {
      e[i][i] = 1;
    }
    return e;
  }
  if (n == 1)
    return a;
  else {
    vector<vector<T>> ans(a.size(), vector<T>(a[0].size(), 0));
    ans = powgyou(a, n / 2);
    ans = keisann(ans, ans);
    if (n % 2) {
      ans = keisann(ans, a);
    }
    return ans;
  }
}

int main() {
  int casenum = 0;
  while (1) {
    casenum++;
    int W, N;
    long long int H;
    cin >> W >> H >> N;
    if (!W)
      break;
    map<long long int, vector<int>> mp;
    vector<vector<Mod>> forspaces(W, vector<Mod>(W));
    for (int y = 0; y < W; ++y) {
      for (int x = 0; x < W; ++x) {
        if (abs(x - y) <= 1)
          forspaces[y][x] = true;
      }
    }
    bool flag = true;
    for (int i = 0; i < N; ++i) {
      int x, y;
      cin >> x >> y;
      x--;
      y--;
      if (!x && !y) {
        flag = false;
      }
      mp[y].push_back(x);
    }
    Mod ans = 0;
    if (flag) {
      for (int i = 0; i < W - 1; ++i) {
        mp[H - 1].push_back(i);
      }
      vector<vector<Mod>> nums(W, vector<Mod>(1));
      nums[0][0] = 1;
      long long int nowy = 0;
      for (auto it = mp.begin(); it != mp.end(); ++it) {
        long long int nexty = it->first;
        vector<int> obs(it->second);
        if (nexty == nowy)
          continue;
        else {
          long long int spaces = nexty - nowy - 1;
          nums = keisann(powgyou(forspaces, spaces), nums);

          vector<vector<Mod>> forobs(forspaces);
          for (int y = 0; y < W; ++y) {
            for (int x = 0; x < W; ++x) {
              if (find(obs.begin(), obs.end(), y) != obs.end())
                forobs[y][x] = false;
            }
          }
          nums = keisann(powgyou(forobs, 1), nums);
          nowy = nexty;
        }
      }
      ans = nums[W - 1][0];
    }

    cout << "Case " << casenum << ": " << ans.num << endl;
  }
  return 0;
}