oj.uz

Submission #970792

# Submission time Handle Problem Language Result Execution time Memory
970792 2024-04-27T09:16:37 Z vjudge1 Boat (APIO16_boat) C++14
27 / 100
 486 ms 4556 KB 
#include<bits/stdc++.h>

using namespace std;

const int N=510, mod=1e9+7;
int fact[N*2], invfact[N*2], inv[N*2];

int binpow(int x, int y){
   int t=1;
   while (y){
      if (y&1) t=1ll*t*x%mod;
      x=1ll*x*x%mod;
      y>>=1;
   }
   return t;
}

void precalc(){
   fact[0]=1;
   for (int i=1; i<N*2; ++i) fact[i]=1ll*fact[i-1]*i%mod;
   invfact[N*2-1]=binpow(fact[N*2-1], mod-2);
   for (int i=N*2-2; i>=0; --i) invfact[i]=1ll*invfact[i+1]*(i+1)%mod;
   for (int i=1; i<N*2; ++i) inv[i]=1ll*invfact[i]*fact[i-1]%mod;
}

int C(int n, int k){
   if (n<0 || k<0 || n<k) return 0;
   return 1ll*fact[n]*invfact[k]%mod*invfact[n-k]%mod;
}

int f[N*2][N], g[N*2][N], sf[N], sg[N], n, a[N], b[N];
vector<int> vals;

int32_t main(){
   ios_base::sync_with_stdio(false);
   cin.tie(nullptr);
   precalc();
   vals.push_back(-1);
   cin >> n;
   for (int i=1; i<=n; ++i) cin >> a[i] >> b[i], vals.push_back(a[i]), vals.push_back(++b[i]);
   sort(vals.begin(), vals.end());
   vals.resize(unique(vals.begin(), vals.end())-vals.begin());
   for (int i=1; i<=n; ++i){
      a[i]=lower_bound(vals.begin(), vals.end(), a[i])-vals.begin();
      b[i]=lower_bound(vals.begin(), vals.end(), b[i])-vals.begin();
   }
   f[0][0]=1;
   for (int i=0; i<(int)vals.size(); ++i) sf[i]=1;
   for (int i=1; i<=n; ++i){
      for (int j=a[i]; j<b[i]; ++j){
         int len=vals[j+1]-vals[j];
         for (int k=1; k<=i && k<=len; ++k){
            g[j][k]=(g[j][k]+1ll*(k==1?sf[j-1]:f[j][k-1])*(len-k+1)%mod*inv[k])%mod;
         }
      }
      for (int j=0; j<(int)vals.size(); ++j) for (int k=0; k<=i; ++k){
         g[j][k]=(g[j][k]+f[j][k])%mod;
         sg[j]=(sg[j]+g[j][k])%mod;
      }
      for (int j=1; j<(int)vals.size(); ++j) sg[j]=(sg[j]+sg[j-1])%mod;
      memcpy(f, g, sizeof f);
      memcpy(sf, sg, sizeof sf);
      memset(g, 0, sizeof g);
      memset(sg, 0, sizeof sg);
   }
   cout << (sf[(int)vals.size()-1]+mod-1)%mod << '\n';
   return 0;
}

Subtask #1
0 / 9.0

# Verdict Execution time Memory Grader output
1 Incorrect 486 ms 4532 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Incorrect 486 ms 4532 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 4444 KB Output is correct
2 Correct 14 ms 4444 KB Output is correct
3 Correct 16 ms 4440 KB Output is correct
4 Correct 16 ms 4444 KB Output is correct
5 Correct 16 ms 4440 KB Output is correct
6 Correct 16 ms 4444 KB Output is correct
7 Correct 15 ms 4444 KB Output is correct
8 Correct 16 ms 4440 KB Output is correct
9 Correct 16 ms 4444 KB Output is correct
10 Correct 16 ms 4440 KB Output is correct
11 Correct 15 ms 4444 KB Output is correct
12 Correct 15 ms 4444 KB Output is correct
13 Correct 14 ms 4444 KB Output is correct
14 Correct 15 ms 4552 KB Output is correct
15 Correct 16 ms 4444 KB Output is correct
16 Correct 13 ms 4444 KB Output is correct
17 Correct 13 ms 4440 KB Output is correct
18 Correct 12 ms 4444 KB Output is correct
19 Correct 12 ms 4444 KB Output is correct
20 Correct 13 ms 4556 KB Output is correct

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Incorrect 486 ms 4532 KB Output isn't correct
2 Halted 0 ms 0 KB -