#include <bits/stdc++.h>
#define ll long long
const ll MOD=1000000007;
using namespace std;
ll n,k;
ll l[605],r[605],dp[605][605],val[605],cnt[605][605],c[605][605],sum[605][605],len[605],C[605][605];
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(){
cin >> n;
for(ll i=1;i<=n;i++){
cin >> l[i] >> r[i];
s.insert(l[i]);
s.insert(r[i]+1);
um[l[i]] = um[r[i] + 1] = 0;
}
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);
C[i][j]%=MOD;
C[i][j]*=power(j,MOD-2);
C[i][j]%=MOD;
}
}
for (ll j=0;j<k;j++) c[0][j] = 1;
for (ll j=0;j<k;j++) C[0][j] = 1;
for(ll i=1;i<k;i++){
c[i][0]=1;
for(ll j=1;j<=min(len[i],n);j++){
c[i][j]=c[i][j-1]*(len[i]+1-j);
c[i][j]%=MOD;
c[i][j]*=power(j,MOD-2);
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]);
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];
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])]);
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;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
640 ms |
12812 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
640 ms |
12812 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
15 ms |
3608 KB |
Output is correct |
2 |
Correct |
14 ms |
3532 KB |
Output is correct |
3 |
Correct |
16 ms |
3600 KB |
Output is correct |
4 |
Correct |
14 ms |
3584 KB |
Output is correct |
5 |
Correct |
14 ms |
3600 KB |
Output is correct |
6 |
Correct |
15 ms |
3492 KB |
Output is correct |
7 |
Correct |
15 ms |
3532 KB |
Output is correct |
8 |
Correct |
15 ms |
3532 KB |
Output is correct |
9 |
Correct |
15 ms |
3508 KB |
Output is correct |
10 |
Correct |
15 ms |
3532 KB |
Output is correct |
11 |
Correct |
14 ms |
3532 KB |
Output is correct |
12 |
Correct |
14 ms |
3500 KB |
Output is correct |
13 |
Correct |
14 ms |
3532 KB |
Output is correct |
14 |
Correct |
15 ms |
3532 KB |
Output is correct |
15 |
Correct |
14 ms |
3532 KB |
Output is correct |
16 |
Correct |
10 ms |
2636 KB |
Output is correct |
17 |
Correct |
8 ms |
2712 KB |
Output is correct |
18 |
Correct |
9 ms |
2764 KB |
Output is correct |
19 |
Correct |
8 ms |
2764 KB |
Output is correct |
20 |
Correct |
9 ms |
2636 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
640 ms |
12812 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |