#include<bits/stdc++.h>
using namespace std;
#define ll long long
const ll mod=1e9+7;
const ll MAXN=502;
ll dp[MAXN][2*MAXN];
ll l1[2*MAXN],r1[2*MAXN];
ll n;
ll a[MAXN],b[MAXN];
ll a1[MAXN],b1[MAXN];
ll inv[MAXN];
ll fastpow(ll x,ll p)
{
if(p==0)return 1;
ll t=fastpow(x,p/2);
t*=t;t%=mod;
if(p%2==1)t*=x;
t%=mod;
return t;
}
int main()
{
cin>>n;
vector<ll>v;
for(int i=1;i<=n;i++)
{
cin>>a[i]>>b[i];
v.push_back(a[i]);
v.push_back(b[i]+1);
}
sort(v.begin(),v.end());
int cnt=0;
for(int i=1;i<v.size();i++)
{
if(v[i]==v[i-1])continue;
cnt++;
l1[cnt]=v[i-1];
r1[cnt]=v[i]-1;
}
for(int i=0;i<2*MAXN;i++)
{
dp[0][i]=1;
}
for(int i=1;i<MAXN;i++)inv[i]=fastpow(i,mod-2);
for(int i=1;i<=cnt;i++)
{
ll t=r1[i]-l1[i]+1;
for(int j=1;j<=n;j++)
{
dp[j][i]=dp[j][i-1];
if(a[j]>r1[i]||b[j]<l1[i])continue;
ll fnaf=t,c=1;
for(int k=j-1;k>=0;k--)
{
dp[j][i]=dp[j][i]+dp[k][i-1]*fnaf;
dp[j][i]%=mod;
if(a[j]<=l1[i]&&b[j]>=r1[i])
{
fnaf=fnaf*(t+c);
fnaf%=mod;
c++;
fnaf*=inv[c];
fnaf%=mod;
}
}
}
}
ll ans=0;
for(ll i=1;i<=n;i++)
{
ans+=dp[i][cnt];ans%=mod;
}
cout<<ans<<endl;
return 0;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:33:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
33 | for(int i=1;i<v.size();i++)
| ~^~~~~~~~~
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
7 ms |
4592 KB |
Output is correct |
| 2 |
Correct |
7 ms |
4332 KB |
Output is correct |
| 3 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 4 |
Correct |
8 ms |
4332 KB |
Output is correct |
| 5 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 6 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 7 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 8 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 9 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 10 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 11 |
Correct |
7 ms |
4332 KB |
Output is correct |
| 12 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 13 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 14 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 15 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 16 |
Correct |
5 ms |
3052 KB |
Output is correct |
| 17 |
Correct |
5 ms |
3180 KB |
Output is correct |
| 18 |
Correct |
5 ms |
3052 KB |
Output is correct |
| 19 |
Correct |
5 ms |
3180 KB |
Output is correct |
| 20 |
Correct |
5 ms |
3052 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
7 ms |
4592 KB |
Output is correct |
| 2 |
Correct |
7 ms |
4332 KB |
Output is correct |
| 3 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 4 |
Correct |
8 ms |
4332 KB |
Output is correct |
| 5 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 6 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 7 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 8 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 9 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 10 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 11 |
Correct |
7 ms |
4332 KB |
Output is correct |
| 12 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 13 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 14 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 15 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 16 |
Correct |
5 ms |
3052 KB |
Output is correct |
| 17 |
Correct |
5 ms |
3180 KB |
Output is correct |
| 18 |
Correct |
5 ms |
3052 KB |
Output is correct |
| 19 |
Correct |
5 ms |
3180 KB |
Output is correct |
| 20 |
Correct |
5 ms |
3052 KB |
Output is correct |
| 21 |
Incorrect |
479 ms |
4360 KB |
Output isn't correct |
| 22 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
6 ms |
876 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
7 ms |
4592 KB |
Output is correct |
| 2 |
Correct |
7 ms |
4332 KB |
Output is correct |
| 3 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 4 |
Correct |
8 ms |
4332 KB |
Output is correct |
| 5 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 6 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 7 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 8 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 9 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 10 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 11 |
Correct |
7 ms |
4332 KB |
Output is correct |
| 12 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 13 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 14 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 15 |
Correct |
6 ms |
4332 KB |
Output is correct |
| 16 |
Correct |
5 ms |
3052 KB |
Output is correct |
| 17 |
Correct |
5 ms |
3180 KB |
Output is correct |
| 18 |
Correct |
5 ms |
3052 KB |
Output is correct |
| 19 |
Correct |
5 ms |
3180 KB |
Output is correct |
| 20 |
Correct |
5 ms |
3052 KB |
Output is correct |
| 21 |
Incorrect |
479 ms |
4360 KB |
Output isn't correct |
| 22 |
Halted |
0 ms |
0 KB |
- |
