#include<bits/stdc++.h>
using namespace std;
int mod=1e9+7;
long long mypow(long long m,long long y){
if(y==0){
return 1;
}
long long p=mypow(m,(y>>1));
p*=p;
p%=mod;
if(y&1){
p*=m;
p%=mod;
}
return p;
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n;
cin>>n;
vector<long long>rev(n+6);
for(int i=0;i<=n+5;i++){
rev[i]=mypow(i,mod-2);
}
vector<pair<int,int>>all(n+1);
vector<int>allind;
for(int i=1;i<=n;i++){
cin>>all[i].first>>all[i].second;
allind.push_back(all[i].first);
allind.push_back(all[i].second);
allind.push_back(all[i].first+1);
allind.push_back(all[i].first-1);
allind.push_back(all[i].second+1);
allind.push_back(all[i].second-1);
}
allind.push_back(0);
sort(allind.begin(),allind.end());
allind.resize(unique(allind.begin(),allind.end())-allind.begin());
vector<vector<long long>>dp(n*10+10,vector<long long>(n*10+10));
vector<long long>ps(n*10+10);
dp[0][0]=1;
for(int i=0;i<n*10+10;i++){
ps[i]=1;
}
for(int i=1;i<=n;i++){
int l=lower_bound(allind.begin(),allind.end(),all[i].first)-allind.begin();
int r=lower_bound(allind.begin(),allind.end(),all[i].second)-allind.begin();
for(int j=l;j<=r;j++){
long long cnt=allind[j]-allind[j-1];
for(int h=n;h>=2;h--){
dp[j][h]+=dp[j][h-1]*(cnt-(h-1))%mod*rev[h]%mod;
dp[j][h]%=mod;
}
dp[j][1]+=ps[j-1]*cnt%mod;
dp[j][1]%=mod;
}
ps[0]=dp[0][0];
for(int i=1;i<=n*10+9;i++){
ps[i]=ps[i-1];
for(int h=0;h<=n;h++){
ps[i]+=dp[i][h];
}
ps[i]%=mod;
}
}
long long res=ps[n*10+8];
res+=mod-1;
res%=mod;
cout<<res<<"\n";
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1343 ms |
197092 KB |
Output is correct |
2 |
Correct |
1332 ms |
197068 KB |
Output is correct |
3 |
Correct |
1326 ms |
197064 KB |
Output is correct |
4 |
Correct |
1329 ms |
197140 KB |
Output is correct |
5 |
Correct |
1357 ms |
197140 KB |
Output is correct |
6 |
Correct |
1346 ms |
197064 KB |
Output is correct |
7 |
Correct |
1325 ms |
197152 KB |
Output is correct |
8 |
Correct |
1353 ms |
197060 KB |
Output is correct |
9 |
Correct |
1368 ms |
197140 KB |
Output is correct |
10 |
Correct |
1334 ms |
197060 KB |
Output is correct |
11 |
Correct |
1370 ms |
197112 KB |
Output is correct |
12 |
Correct |
1353 ms |
197064 KB |
Output is correct |
13 |
Correct |
1337 ms |
197068 KB |
Output is correct |
14 |
Correct |
1355 ms |
197060 KB |
Output is correct |
15 |
Correct |
1342 ms |
197068 KB |
Output is correct |
16 |
Correct |
1363 ms |
197064 KB |
Output is correct |
17 |
Correct |
1334 ms |
197064 KB |
Output is correct |
18 |
Correct |
1346 ms |
197060 KB |
Output is correct |
19 |
Correct |
1381 ms |
197064 KB |
Output is correct |
20 |
Correct |
1347 ms |
197060 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1343 ms |
197092 KB |
Output is correct |
2 |
Correct |
1332 ms |
197068 KB |
Output is correct |
3 |
Correct |
1326 ms |
197064 KB |
Output is correct |
4 |
Correct |
1329 ms |
197140 KB |
Output is correct |
5 |
Correct |
1357 ms |
197140 KB |
Output is correct |
6 |
Correct |
1346 ms |
197064 KB |
Output is correct |
7 |
Correct |
1325 ms |
197152 KB |
Output is correct |
8 |
Correct |
1353 ms |
197060 KB |
Output is correct |
9 |
Correct |
1368 ms |
197140 KB |
Output is correct |
10 |
Correct |
1334 ms |
197060 KB |
Output is correct |
11 |
Correct |
1370 ms |
197112 KB |
Output is correct |
12 |
Correct |
1353 ms |
197064 KB |
Output is correct |
13 |
Correct |
1337 ms |
197068 KB |
Output is correct |
14 |
Correct |
1355 ms |
197060 KB |
Output is correct |
15 |
Correct |
1342 ms |
197068 KB |
Output is correct |
16 |
Correct |
1363 ms |
197064 KB |
Output is correct |
17 |
Correct |
1334 ms |
197064 KB |
Output is correct |
18 |
Correct |
1346 ms |
197060 KB |
Output is correct |
19 |
Correct |
1381 ms |
197064 KB |
Output is correct |
20 |
Correct |
1347 ms |
197060 KB |
Output is correct |
21 |
Execution timed out |
2073 ms |
196992 KB |
Time limit exceeded |
22 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
41 ms |
8364 KB |
Output is correct |
2 |
Correct |
36 ms |
8276 KB |
Output is correct |
3 |
Correct |
39 ms |
8344 KB |
Output is correct |
4 |
Correct |
42 ms |
8276 KB |
Output is correct |
5 |
Correct |
43 ms |
8276 KB |
Output is correct |
6 |
Correct |
56 ms |
8276 KB |
Output is correct |
7 |
Correct |
59 ms |
8344 KB |
Output is correct |
8 |
Correct |
56 ms |
8256 KB |
Output is correct |
9 |
Correct |
55 ms |
8276 KB |
Output is correct |
10 |
Correct |
56 ms |
8276 KB |
Output is correct |
11 |
Correct |
44 ms |
8252 KB |
Output is correct |
12 |
Correct |
37 ms |
8276 KB |
Output is correct |
13 |
Correct |
41 ms |
8252 KB |
Output is correct |
14 |
Correct |
43 ms |
8276 KB |
Output is correct |
15 |
Correct |
46 ms |
8340 KB |
Output is correct |
16 |
Correct |
26 ms |
8276 KB |
Output is correct |
17 |
Correct |
24 ms |
8276 KB |
Output is correct |
18 |
Correct |
25 ms |
8276 KB |
Output is correct |
19 |
Correct |
26 ms |
8276 KB |
Output is correct |
20 |
Correct |
29 ms |
8276 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1343 ms |
197092 KB |
Output is correct |
2 |
Correct |
1332 ms |
197068 KB |
Output is correct |
3 |
Correct |
1326 ms |
197064 KB |
Output is correct |
4 |
Correct |
1329 ms |
197140 KB |
Output is correct |
5 |
Correct |
1357 ms |
197140 KB |
Output is correct |
6 |
Correct |
1346 ms |
197064 KB |
Output is correct |
7 |
Correct |
1325 ms |
197152 KB |
Output is correct |
8 |
Correct |
1353 ms |
197060 KB |
Output is correct |
9 |
Correct |
1368 ms |
197140 KB |
Output is correct |
10 |
Correct |
1334 ms |
197060 KB |
Output is correct |
11 |
Correct |
1370 ms |
197112 KB |
Output is correct |
12 |
Correct |
1353 ms |
197064 KB |
Output is correct |
13 |
Correct |
1337 ms |
197068 KB |
Output is correct |
14 |
Correct |
1355 ms |
197060 KB |
Output is correct |
15 |
Correct |
1342 ms |
197068 KB |
Output is correct |
16 |
Correct |
1363 ms |
197064 KB |
Output is correct |
17 |
Correct |
1334 ms |
197064 KB |
Output is correct |
18 |
Correct |
1346 ms |
197060 KB |
Output is correct |
19 |
Correct |
1381 ms |
197064 KB |
Output is correct |
20 |
Correct |
1347 ms |
197060 KB |
Output is correct |
21 |
Execution timed out |
2073 ms |
196992 KB |
Time limit exceeded |
22 |
Halted |
0 ms |
0 KB |
- |