#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=502;
const int mod=1e9+7;
int used[N],sum[N],dp[N],ndp[N],choose[N],rev[N];
vector<pair<int,int> > ope;
int binpow(int x,int y){
int tich=1;
while(y){
if(y&1){
tich*=x;
tich%=mod;
}
x*=x;
x%=mod;
y>>=1;
}
return tich;
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
int n,i,j,k,l;
cin>>n;
for(i=1;i<=n;i++){
cin>>j>>k;
k++;
ope.push_back({j,i});
ope.push_back({k,i});
}
sort(ope.begin(),ope.end());
rev[0]=1;
for(i=1;i<=n;i++){
rev[i]=binpow(i,mod-2);
}
i=0;
j=0;
dp[0]=1;
while(i<ope.size()){
while(j<ope.size()&&ope[j].first==ope[i].first){
used[ope[j].second]^=1;
j++;
}
if(j==ope.size()){
break;
}
for(k=1;k<=n;k++){
sum[k]=sum[k-1]+used[k];
choose[k]=0;
//cout<<sum[k]<<' ';
}
//cout<<endl;
int len=ope[j].first-ope[i].first,val=sum[n],c1,c2;
//cout<<len<<' '<<val<<endl;
for(k=1;k<=val;k++){
c1=len;
c2=1;
assert(k<=n);
for(l=0;l<min(k,len+1);l++){
choose[k]+=c1*c2;
choose[k]%=mod;
c1=c1*(len-l-1);
c1%=mod;
c1=c1*rev[l+2];
c1%=mod;
c2=c2*(k-l-1);
c2%=mod;
c2=c2*rev[l+1];
c2%=mod;
}
}
for(k=0;k<=n;k++){
ndp[k]=dp[k];
if(used[k]){
for(l=0;l<k;l++){
ndp[k]+=dp[l]*choose[sum[k]-sum[l]];
// if(k==2){
// cout<<l<<' '<<dp[l]<<' '<<choose[sum[k]-sum[l]]<<' '<<sum[k]-sum[l]<<endl;
// }
ndp[k]%=mod;
}
}
}
for(k=0;k<=n;k++){
dp[k]=ndp[k];
// cout<<dp[k]<<' ';
}
//cout<<"cac"<<endl;
i=j;
}
int ans=0;
for(i=1;i<=n;i++){
ans+=dp[i];
if(ans>=mod){
ans-=mod;
}
}
cout<<ans;
}
/*
3
1 2
3 4
5 6
3
1 2
4 5
7 8
26
*/
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:40:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
while(i<ope.size()){
~^~~~~~~~~~~
boat.cpp:41:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
while(j<ope.size()&&ope[j].first==ope[i].first){
~^~~~~~~~~~~
boat.cpp:45:7: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(j==ope.size()){
~^~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
376 KB |
Output is correct |
2 |
Correct |
5 ms |
376 KB |
Output is correct |
3 |
Correct |
5 ms |
376 KB |
Output is correct |
4 |
Correct |
5 ms |
376 KB |
Output is correct |
5 |
Correct |
5 ms |
376 KB |
Output is correct |
6 |
Correct |
5 ms |
376 KB |
Output is correct |
7 |
Correct |
6 ms |
376 KB |
Output is correct |
8 |
Correct |
5 ms |
376 KB |
Output is correct |
9 |
Correct |
5 ms |
376 KB |
Output is correct |
10 |
Correct |
5 ms |
376 KB |
Output is correct |
11 |
Correct |
5 ms |
376 KB |
Output is correct |
12 |
Correct |
5 ms |
376 KB |
Output is correct |
13 |
Correct |
5 ms |
504 KB |
Output is correct |
14 |
Correct |
5 ms |
376 KB |
Output is correct |
15 |
Correct |
5 ms |
376 KB |
Output is correct |
16 |
Correct |
4 ms |
376 KB |
Output is correct |
17 |
Correct |
4 ms |
376 KB |
Output is correct |
18 |
Correct |
4 ms |
376 KB |
Output is correct |
19 |
Correct |
4 ms |
376 KB |
Output is correct |
20 |
Correct |
3 ms |
376 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
376 KB |
Output is correct |
2 |
Correct |
5 ms |
376 KB |
Output is correct |
3 |
Correct |
5 ms |
376 KB |
Output is correct |
4 |
Correct |
5 ms |
376 KB |
Output is correct |
5 |
Correct |
5 ms |
376 KB |
Output is correct |
6 |
Correct |
5 ms |
376 KB |
Output is correct |
7 |
Correct |
6 ms |
376 KB |
Output is correct |
8 |
Correct |
5 ms |
376 KB |
Output is correct |
9 |
Correct |
5 ms |
376 KB |
Output is correct |
10 |
Correct |
5 ms |
376 KB |
Output is correct |
11 |
Correct |
5 ms |
376 KB |
Output is correct |
12 |
Correct |
5 ms |
376 KB |
Output is correct |
13 |
Correct |
5 ms |
504 KB |
Output is correct |
14 |
Correct |
5 ms |
376 KB |
Output is correct |
15 |
Correct |
5 ms |
376 KB |
Output is correct |
16 |
Correct |
4 ms |
376 KB |
Output is correct |
17 |
Correct |
4 ms |
376 KB |
Output is correct |
18 |
Correct |
4 ms |
376 KB |
Output is correct |
19 |
Correct |
4 ms |
376 KB |
Output is correct |
20 |
Correct |
3 ms |
376 KB |
Output is correct |
21 |
Correct |
231 ms |
448 KB |
Output is correct |
22 |
Correct |
222 ms |
508 KB |
Output is correct |
23 |
Correct |
208 ms |
376 KB |
Output is correct |
24 |
Correct |
224 ms |
352 KB |
Output is correct |
25 |
Correct |
218 ms |
376 KB |
Output is correct |
26 |
Correct |
312 ms |
452 KB |
Output is correct |
27 |
Correct |
319 ms |
376 KB |
Output is correct |
28 |
Correct |
387 ms |
504 KB |
Output is correct |
29 |
Correct |
309 ms |
376 KB |
Output is correct |
30 |
Correct |
7 ms |
376 KB |
Output is correct |
31 |
Correct |
7 ms |
376 KB |
Output is correct |
32 |
Correct |
6 ms |
376 KB |
Output is correct |
33 |
Correct |
7 ms |
376 KB |
Output is correct |
34 |
Correct |
8 ms |
376 KB |
Output is correct |
35 |
Correct |
6 ms |
376 KB |
Output is correct |
36 |
Correct |
7 ms |
376 KB |
Output is correct |
37 |
Correct |
12 ms |
424 KB |
Output is correct |
38 |
Correct |
6 ms |
376 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
376 KB |
Output is correct |
2 |
Correct |
5 ms |
376 KB |
Output is correct |
3 |
Correct |
6 ms |
376 KB |
Output is correct |
4 |
Correct |
6 ms |
376 KB |
Output is correct |
5 |
Correct |
6 ms |
376 KB |
Output is correct |
6 |
Correct |
10 ms |
376 KB |
Output is correct |
7 |
Correct |
9 ms |
376 KB |
Output is correct |
8 |
Correct |
10 ms |
376 KB |
Output is correct |
9 |
Correct |
10 ms |
376 KB |
Output is correct |
10 |
Correct |
10 ms |
376 KB |
Output is correct |
11 |
Correct |
6 ms |
376 KB |
Output is correct |
12 |
Correct |
5 ms |
376 KB |
Output is correct |
13 |
Correct |
6 ms |
376 KB |
Output is correct |
14 |
Correct |
5 ms |
376 KB |
Output is correct |
15 |
Correct |
7 ms |
376 KB |
Output is correct |
16 |
Correct |
4 ms |
376 KB |
Output is correct |
17 |
Correct |
4 ms |
380 KB |
Output is correct |
18 |
Correct |
4 ms |
376 KB |
Output is correct |
19 |
Correct |
4 ms |
376 KB |
Output is correct |
20 |
Correct |
4 ms |
376 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
376 KB |
Output is correct |
2 |
Correct |
5 ms |
376 KB |
Output is correct |
3 |
Correct |
5 ms |
376 KB |
Output is correct |
4 |
Correct |
5 ms |
376 KB |
Output is correct |
5 |
Correct |
5 ms |
376 KB |
Output is correct |
6 |
Correct |
5 ms |
376 KB |
Output is correct |
7 |
Correct |
6 ms |
376 KB |
Output is correct |
8 |
Correct |
5 ms |
376 KB |
Output is correct |
9 |
Correct |
5 ms |
376 KB |
Output is correct |
10 |
Correct |
5 ms |
376 KB |
Output is correct |
11 |
Correct |
5 ms |
376 KB |
Output is correct |
12 |
Correct |
5 ms |
376 KB |
Output is correct |
13 |
Correct |
5 ms |
504 KB |
Output is correct |
14 |
Correct |
5 ms |
376 KB |
Output is correct |
15 |
Correct |
5 ms |
376 KB |
Output is correct |
16 |
Correct |
4 ms |
376 KB |
Output is correct |
17 |
Correct |
4 ms |
376 KB |
Output is correct |
18 |
Correct |
4 ms |
376 KB |
Output is correct |
19 |
Correct |
4 ms |
376 KB |
Output is correct |
20 |
Correct |
3 ms |
376 KB |
Output is correct |
21 |
Correct |
231 ms |
448 KB |
Output is correct |
22 |
Correct |
222 ms |
508 KB |
Output is correct |
23 |
Correct |
208 ms |
376 KB |
Output is correct |
24 |
Correct |
224 ms |
352 KB |
Output is correct |
25 |
Correct |
218 ms |
376 KB |
Output is correct |
26 |
Correct |
312 ms |
452 KB |
Output is correct |
27 |
Correct |
319 ms |
376 KB |
Output is correct |
28 |
Correct |
387 ms |
504 KB |
Output is correct |
29 |
Correct |
309 ms |
376 KB |
Output is correct |
30 |
Correct |
7 ms |
376 KB |
Output is correct |
31 |
Correct |
7 ms |
376 KB |
Output is correct |
32 |
Correct |
6 ms |
376 KB |
Output is correct |
33 |
Correct |
7 ms |
376 KB |
Output is correct |
34 |
Correct |
8 ms |
376 KB |
Output is correct |
35 |
Correct |
6 ms |
376 KB |
Output is correct |
36 |
Correct |
7 ms |
376 KB |
Output is correct |
37 |
Correct |
12 ms |
424 KB |
Output is correct |
38 |
Correct |
6 ms |
376 KB |
Output is correct |
39 |
Correct |
6 ms |
376 KB |
Output is correct |
40 |
Correct |
5 ms |
376 KB |
Output is correct |
41 |
Correct |
6 ms |
376 KB |
Output is correct |
42 |
Correct |
6 ms |
376 KB |
Output is correct |
43 |
Correct |
6 ms |
376 KB |
Output is correct |
44 |
Correct |
10 ms |
376 KB |
Output is correct |
45 |
Correct |
9 ms |
376 KB |
Output is correct |
46 |
Correct |
10 ms |
376 KB |
Output is correct |
47 |
Correct |
10 ms |
376 KB |
Output is correct |
48 |
Correct |
10 ms |
376 KB |
Output is correct |
49 |
Correct |
6 ms |
376 KB |
Output is correct |
50 |
Correct |
5 ms |
376 KB |
Output is correct |
51 |
Correct |
6 ms |
376 KB |
Output is correct |
52 |
Correct |
5 ms |
376 KB |
Output is correct |
53 |
Correct |
7 ms |
376 KB |
Output is correct |
54 |
Correct |
4 ms |
376 KB |
Output is correct |
55 |
Correct |
4 ms |
380 KB |
Output is correct |
56 |
Correct |
4 ms |
376 KB |
Output is correct |
57 |
Correct |
4 ms |
376 KB |
Output is correct |
58 |
Correct |
4 ms |
376 KB |
Output is correct |
59 |
Correct |
499 ms |
480 KB |
Output is correct |
60 |
Correct |
453 ms |
456 KB |
Output is correct |
61 |
Correct |
430 ms |
504 KB |
Output is correct |
62 |
Correct |
505 ms |
484 KB |
Output is correct |
63 |
Correct |
477 ms |
504 KB |
Output is correct |
64 |
Correct |
940 ms |
456 KB |
Output is correct |
65 |
Correct |
941 ms |
376 KB |
Output is correct |
66 |
Correct |
945 ms |
448 KB |
Output is correct |
67 |
Correct |
986 ms |
444 KB |
Output is correct |
68 |
Correct |
936 ms |
504 KB |
Output is correct |
69 |
Correct |
393 ms |
456 KB |
Output is correct |
70 |
Correct |
397 ms |
376 KB |
Output is correct |
71 |
Correct |
392 ms |
376 KB |
Output is correct |
72 |
Correct |
408 ms |
376 KB |
Output is correct |
73 |
Correct |
422 ms |
504 KB |
Output is correct |
74 |
Correct |
72 ms |
376 KB |
Output is correct |
75 |
Correct |
68 ms |
376 KB |
Output is correct |
76 |
Correct |
73 ms |
424 KB |
Output is correct |
77 |
Correct |
73 ms |
376 KB |
Output is correct |
78 |
Correct |
74 ms |
504 KB |
Output is correct |