#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
#define pii pair<int,int>
#define LL long long
#define st first
#define nd second
#define endl '\n'
using namespace std;
const int MAXN=505;
int dp[MAXN][MAXN*2],n,a[MAXN],b[MAXN],mod=1e9+7;
vector<int> po;
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin>>n;
for(int i=1;i<=n;++i) {
cin>>a[i]>>b[i];
po.pb(a[i]);
po.pb(b[i]);
po.pb(b[i]+1);
}
sort(po.begin(),po.end());
po.resize(unique(po.begin(),po.end())-po.begin());
for(int i=1;i<=n;++i) {
a[i]=lower_bound(po.begin(),po.end(),a[i])-po.begin();
b[i]=lower_bound(po.begin(),po.end(),b[i])-po.begin();
}
for(int j=0;j<po.size();++j)
dp[n+1][j]=1;
for(int i=n;i>=1;--i) {
for(int j=0;j<po.size();++j) {
dp[i][j]=dp[i+1][j];
for(int k=max(a[i]+1,j+1);k<=b[i]+1;++k) {
dp[i][j]+=(1LL*(po[k]-po[k-1])*dp[i+1][k])%mod;
if(dp[i][j]>=mod)
dp[i][j]-=mod;
//cout<<"doing "<<i<<" "<<k<<" "<<po[k]-po[k-1]<<" "<<dp[i+1][k]<<endl;
}
//cout<<i<<" "<<j<<" "<<po[j]<<" "<<dp[i][j]<<endl;
}
}
cout<<(dp[1][0]-1+mod)%mod<< endl;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:32:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j=0;j<po.size();++j)
^
boat.cpp:35:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j=0;j<po.size();++j) {
^
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 2 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 3 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 4 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 5 |
Correct |
3 ms |
4176 KB |
Output is correct |
| 6 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 7 |
Correct |
3 ms |
4176 KB |
Output is correct |
| 8 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 9 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 10 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 11 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 12 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 13 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 14 |
Correct |
3 ms |
4176 KB |
Output is correct |
| 15 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 16 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 17 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 18 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 19 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 20 |
Correct |
3 ms |
4176 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 2 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 3 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 4 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 5 |
Correct |
3 ms |
4176 KB |
Output is correct |
| 6 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 7 |
Correct |
3 ms |
4176 KB |
Output is correct |
| 8 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 9 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 10 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 11 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 12 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 13 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 14 |
Correct |
3 ms |
4176 KB |
Output is correct |
| 15 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 16 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 17 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 18 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 19 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 20 |
Correct |
3 ms |
4176 KB |
Output is correct |
| 21 |
Execution timed out |
2000 ms |
4176 KB |
Execution timed out |
| 22 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
26 ms |
4176 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 2 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 3 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 4 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 5 |
Correct |
3 ms |
4176 KB |
Output is correct |
| 6 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 7 |
Correct |
3 ms |
4176 KB |
Output is correct |
| 8 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 9 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 10 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 11 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 12 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 13 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 14 |
Correct |
3 ms |
4176 KB |
Output is correct |
| 15 |
Correct |
6 ms |
4176 KB |
Output is correct |
| 16 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 17 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 18 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 19 |
Correct |
0 ms |
4176 KB |
Output is correct |
| 20 |
Correct |
3 ms |
4176 KB |
Output is correct |
| 21 |
Execution timed out |
2000 ms |
4176 KB |
Execution timed out |
| 22 |
Halted |
0 ms |
0 KB |
- |
