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Submission #27791

# Submission time Handle Problem Language Result Execution time Memory
27791 2017-07-14T06:17:06 Z sampriti Boat (APIO16_boat) C++14
9 / 100
 273 ms 6148 KB 
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <cstring>

#define MOD 1000000007LL

using namespace std;

int A[500], B[500];
vector<int> T;
int start_i[500], end_i[500];
long long dp[501][1000 + 10];
long long pre_inv[501];

long long modpow(long long base, long long exp) {
  long long res = 1;

  while(exp) {
    if(exp & 1) res = (res * base) % MOD;
    base = (base * base) % MOD;
    exp >>= 1;
  }

  return res;
}

int main() {
  ios::sync_with_stdio(false); cin.tie(0);

  int N; cin >> N;
  for(int i = 0; i < N; i++) {
    cin >> A[i] >> B[i];
    T.push_back(A[i]);
    T.push_back(B[i] + 1);
  }

  for(int i = 1; i <= N; i++) {
    pre_inv[i] = modpow(i, MOD - 2);
  }

  sort(T.begin(), T.end());
  T.resize(unique(T.begin(), T.end()) - T.begin());

  int M = T.size();

  for(int i = 0; i < N; i++) {
    start_i[i] = lower_bound(T.begin(), T.end(), A[i]) - T.begin();
    end_i[i] = upper_bound(T.begin(), T.end(), B[i]) - T.begin();
  }

  for(int j = 0; j < M; j++) dp[N][j] = 1;

  for(int i = N - 1; i >= 0; i--) {
    for(int j = start_i[i]; j < end_i[i]; j++) {
      int len = T[j + 1] - T[j];

      dp[i][j] += len * dp[i + 1][j + 1];
      dp[i][j] %= MOD;

      int cnt = 1;
      long long curr = len - 1;
      for(int k = i + 1; k < N; k++) {
        if(start_i[k] <= j && j < end_i[k]) {
          cnt++;
          curr = (curr * (len + cnt - 2)) % MOD;
          curr = (curr * pre_inv[cnt]) % MOD;
          dp[i][j] += curr * dp[k + 1][j + 1];
          dp[i][j] %= MOD;
        }
      }
    }

    for(int j = M - 1; j >= 0; j--) {
      dp[i][j] += dp[i][j + 1];
    }
    for(int j = M - 1; j >= 0; j--) {
      dp[i][j] += dp[i + 1][j];
    }
  }

  cout << (dp[0][0] - 1 + MOD) % MOD << endl;

  // for(int j = 0; j < M; j++) cout << setw(5) << T[j];
  // cout << endl << endl;
  // for(int i = 0; i < N; i++) {
  //   for(int j = 0; j < M; j++) {
  //     cout << setw(5) << dp[i][j];
  //   }
  //   cout << endl;
  // }
}

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 6148 KB Output is correct
2 Correct 3 ms 6148 KB Output is correct
3 Correct 6 ms 6148 KB Output is correct
4 Correct 0 ms 6148 KB Output is correct
5 Correct 6 ms 6148 KB Output is correct
6 Correct 0 ms 6148 KB Output is correct
7 Correct 0 ms 6148 KB Output is correct
8 Correct 3 ms 6148 KB Output is correct
9 Correct 3 ms 6148 KB Output is correct
10 Correct 0 ms 6148 KB Output is correct
11 Correct 3 ms 6148 KB Output is correct
12 Correct 3 ms 6148 KB Output is correct
13 Correct 0 ms 6148 KB Output is correct
14 Correct 3 ms 6148 KB Output is correct
15 Correct 0 ms 6148 KB Output is correct
16 Correct 0 ms 6148 KB Output is correct
17 Correct 3 ms 6148 KB Output is correct
18 Correct 0 ms 6148 KB Output is correct
19 Correct 0 ms 6148 KB Output is correct
20 Correct 0 ms 6148 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 6148 KB Output is correct
2 Correct 3 ms 6148 KB Output is correct
3 Correct 6 ms 6148 KB Output is correct
4 Correct 0 ms 6148 KB Output is correct
5 Correct 6 ms 6148 KB Output is correct
6 Correct 0 ms 6148 KB Output is correct
7 Correct 0 ms 6148 KB Output is correct
8 Correct 3 ms 6148 KB Output is correct
9 Correct 3 ms 6148 KB Output is correct
10 Correct 0 ms 6148 KB Output is correct
11 Correct 3 ms 6148 KB Output is correct
12 Correct 3 ms 6148 KB Output is correct
13 Correct 0 ms 6148 KB Output is correct
14 Correct 3 ms 6148 KB Output is correct
15 Correct 0 ms 6148 KB Output is correct
16 Correct 0 ms 6148 KB Output is correct
17 Correct 3 ms 6148 KB Output is correct
18 Correct 0 ms 6148 KB Output is correct
19 Correct 0 ms 6148 KB Output is correct
20 Correct 0 ms 6148 KB Output is correct
21 Incorrect 273 ms 6148 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 3 ms 6148 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 6148 KB Output is correct
2 Correct 3 ms 6148 KB Output is correct
3 Correct 6 ms 6148 KB Output is correct
4 Correct 0 ms 6148 KB Output is correct
5 Correct 6 ms 6148 KB Output is correct
6 Correct 0 ms 6148 KB Output is correct
7 Correct 0 ms 6148 KB Output is correct
8 Correct 3 ms 6148 KB Output is correct
9 Correct 3 ms 6148 KB Output is correct
10 Correct 0 ms 6148 KB Output is correct
11 Correct 3 ms 6148 KB Output is correct
12 Correct 3 ms 6148 KB Output is correct
13 Correct 0 ms 6148 KB Output is correct
14 Correct 3 ms 6148 KB Output is correct
15 Correct 0 ms 6148 KB Output is correct
16 Correct 0 ms 6148 KB Output is correct
17 Correct 3 ms 6148 KB Output is correct
18 Correct 0 ms 6148 KB Output is correct
19 Correct 0 ms 6148 KB Output is correct
20 Correct 0 ms 6148 KB Output is correct
21 Incorrect 273 ms 6148 KB Output isn't correct
22 Halted 0 ms 0 KB -