#include <bits/stdc++.h>
#define ll long long
const ll MOD=1000000007;
using namespace std;
ll n,k;
ll l[505],r[505],dp[505][1005],val[1005],cnt[505][1005],c[505][1005],sum[505][1005],len[1005],C[505][505];
unordered_map<ll,ll>um;
set<ll>s;
ll power(ll x,ll y){
ll res=1;
while(y){
if(y&1){
res=res*x;
if(res>=MOD) res%=MOD;
}
y>>=1;
x=x*x;
if(x>=MOD) x%=MOD;
}
return res;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n;
for(ll i=1;i<=n;i++){
cin >> l[i] >> r[i];
s.insert(l[i]);
s.insert(r[i]+1);
}
for(auto i=s.begin();i!=s.end();++i){
um[*i]=++k;
val[k]=*i;
if(k>1) len[k-1]=val[k]-val[k-1];
}
for(ll i=0;i<=n;i++){
C[i][0]=1;
for(ll j=1;j<=i;j++){
C[i][j]=C[i][j-1]*(i+1-j);
if(C[i][j]>=MOD) C[i][j]%=MOD;
C[i][j]*=power(j,MOD-2);
if(C[i][j]>=MOD) C[i][j]%=MOD;
}
}
for(ll i=1;i<k;i++){
c[i][0]=1;
for(ll j=1;j<=n;j++){
if(j>len[i]) sum[i][j]=sum[i][j-1];
else{
c[i][j]=c[i][j-1]*(len[i]+1-j);
if(c[i][j]>=MOD) c[i][j]%=MOD;
c[i][j]*=power(j,MOD-2);
if(c[i][j]>=MOD) c[i][j]%=MOD;
}
// cout << i << ' ' << j << ' ' << c[i][j] << '\n';
}
}
for(ll i=1;i<k;i++){
for(ll j=1;j<=min(len[i],n);j++){
ll res=0;
for(ll t=1;t<=j;t++){
res+=(c[i][t]*C[j-1][t-1]);
if(res>=MOD) res%=MOD;
}
sum[i][j]=res;
}
}
for(ll i=1;i<=n;i++){
for(ll j=1;j<k;j++){
if(l[i]<=val[j] && val[j]<=r[i]){
cnt[i][j]=cnt[i-1][j]+1;
}
else cnt[i][j]=cnt[i-1][j];
// cout << i << ' ' << j << ' ' << cnt[i][j] << '\n';
}
}
for(ll i=0;i<=n;i++){dp[i][0]=1;}
for(ll i=0;i<=n;i++){
for(ll j=1;j<k;j++){
dp[i][j]+=dp[i][j-1];
if(dp[i][j]>=MOD) dp[i][j]%=MOD;
for(ll t=0;t<i;t++){
if(l[t+1]<=val[j] && val[j]<=r[t+1]){
ll p=cnt[i][j]-cnt[t][j];
dp[i][j]+=(dp[t][j-1]*sum[j][min(p,len[j])]);
if(dp[i][j]>=MOD) dp[i][j]%=MOD;
}
// if(i==1 && j==2) cout << cnt[i][j] << '\n';
}
// cout << i << ' ' << j << ' ' << dp[i][j] << '\n';
}
}
cout << (dp[n][k-1]-1+MOD)%MOD;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
556 ms |
18128 KB |
Output is correct |
2 |
Correct |
519 ms |
18192 KB |
Output is correct |
3 |
Correct |
537 ms |
18284 KB |
Output is correct |
4 |
Correct |
520 ms |
18124 KB |
Output is correct |
5 |
Correct |
521 ms |
18228 KB |
Output is correct |
6 |
Correct |
401 ms |
18180 KB |
Output is correct |
7 |
Correct |
413 ms |
18256 KB |
Output is correct |
8 |
Correct |
407 ms |
18220 KB |
Output is correct |
9 |
Correct |
415 ms |
18116 KB |
Output is correct |
10 |
Correct |
407 ms |
18196 KB |
Output is correct |
11 |
Correct |
396 ms |
18148 KB |
Output is correct |
12 |
Correct |
428 ms |
18204 KB |
Output is correct |
13 |
Correct |
402 ms |
18184 KB |
Output is correct |
14 |
Correct |
408 ms |
18192 KB |
Output is correct |
15 |
Correct |
417 ms |
18116 KB |
Output is correct |
16 |
Correct |
142 ms |
10212 KB |
Output is correct |
17 |
Correct |
144 ms |
10416 KB |
Output is correct |
18 |
Correct |
138 ms |
10288 KB |
Output is correct |
19 |
Correct |
143 ms |
10444 KB |
Output is correct |
20 |
Correct |
147 ms |
10304 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
556 ms |
18128 KB |
Output is correct |
2 |
Correct |
519 ms |
18192 KB |
Output is correct |
3 |
Correct |
537 ms |
18284 KB |
Output is correct |
4 |
Correct |
520 ms |
18124 KB |
Output is correct |
5 |
Correct |
521 ms |
18228 KB |
Output is correct |
6 |
Correct |
401 ms |
18180 KB |
Output is correct |
7 |
Correct |
413 ms |
18256 KB |
Output is correct |
8 |
Correct |
407 ms |
18220 KB |
Output is correct |
9 |
Correct |
415 ms |
18116 KB |
Output is correct |
10 |
Correct |
407 ms |
18196 KB |
Output is correct |
11 |
Correct |
396 ms |
18148 KB |
Output is correct |
12 |
Correct |
428 ms |
18204 KB |
Output is correct |
13 |
Correct |
402 ms |
18184 KB |
Output is correct |
14 |
Correct |
408 ms |
18192 KB |
Output is correct |
15 |
Correct |
417 ms |
18116 KB |
Output is correct |
16 |
Correct |
142 ms |
10212 KB |
Output is correct |
17 |
Correct |
144 ms |
10416 KB |
Output is correct |
18 |
Correct |
138 ms |
10288 KB |
Output is correct |
19 |
Correct |
143 ms |
10444 KB |
Output is correct |
20 |
Correct |
147 ms |
10304 KB |
Output is correct |
21 |
Incorrect |
619 ms |
17804 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
14 ms |
3788 KB |
Output is correct |
2 |
Correct |
14 ms |
3788 KB |
Output is correct |
3 |
Correct |
14 ms |
3752 KB |
Output is correct |
4 |
Correct |
14 ms |
3788 KB |
Output is correct |
5 |
Correct |
14 ms |
3788 KB |
Output is correct |
6 |
Correct |
16 ms |
3768 KB |
Output is correct |
7 |
Correct |
15 ms |
3740 KB |
Output is correct |
8 |
Correct |
15 ms |
3796 KB |
Output is correct |
9 |
Correct |
15 ms |
3788 KB |
Output is correct |
10 |
Correct |
15 ms |
3788 KB |
Output is correct |
11 |
Correct |
15 ms |
3788 KB |
Output is correct |
12 |
Correct |
14 ms |
3796 KB |
Output is correct |
13 |
Correct |
15 ms |
3736 KB |
Output is correct |
14 |
Correct |
14 ms |
3712 KB |
Output is correct |
15 |
Correct |
14 ms |
3756 KB |
Output is correct |
16 |
Correct |
9 ms |
2764 KB |
Output is correct |
17 |
Correct |
9 ms |
2764 KB |
Output is correct |
18 |
Correct |
8 ms |
2764 KB |
Output is correct |
19 |
Correct |
8 ms |
2764 KB |
Output is correct |
20 |
Correct |
8 ms |
2764 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
556 ms |
18128 KB |
Output is correct |
2 |
Correct |
519 ms |
18192 KB |
Output is correct |
3 |
Correct |
537 ms |
18284 KB |
Output is correct |
4 |
Correct |
520 ms |
18124 KB |
Output is correct |
5 |
Correct |
521 ms |
18228 KB |
Output is correct |
6 |
Correct |
401 ms |
18180 KB |
Output is correct |
7 |
Correct |
413 ms |
18256 KB |
Output is correct |
8 |
Correct |
407 ms |
18220 KB |
Output is correct |
9 |
Correct |
415 ms |
18116 KB |
Output is correct |
10 |
Correct |
407 ms |
18196 KB |
Output is correct |
11 |
Correct |
396 ms |
18148 KB |
Output is correct |
12 |
Correct |
428 ms |
18204 KB |
Output is correct |
13 |
Correct |
402 ms |
18184 KB |
Output is correct |
14 |
Correct |
408 ms |
18192 KB |
Output is correct |
15 |
Correct |
417 ms |
18116 KB |
Output is correct |
16 |
Correct |
142 ms |
10212 KB |
Output is correct |
17 |
Correct |
144 ms |
10416 KB |
Output is correct |
18 |
Correct |
138 ms |
10288 KB |
Output is correct |
19 |
Correct |
143 ms |
10444 KB |
Output is correct |
20 |
Correct |
147 ms |
10304 KB |
Output is correct |
21 |
Incorrect |
619 ms |
17804 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |