#include<bits/stdc++.h>
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#define MAXN 5007
using namespace std;
struct group{
int from,to;
}s[2*MAXN];
const long long mod=1e9+7;
int n,a[MAXN],b[MAXN],m;
vector<int> pos;
bool in(group g,int id){
return g.from>=a[id] and g.to<=b[id];
}
long long dp[2][MAXN][507][2];
long long invfact[MAXN];
long long cc[507][MAXN];
long long comb(int x,int g){
return cc[x][g];
}
long long power(long long a,int b){
if(b==0)return 1;
if(b==1)return a;
if(b==2)return (a*a)%mod;
if(b%2==0)return power(power(a,b/2),2);
return (a*power(power(a,b/2),2));
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin>>n;
for(int i=1;i<=n;i++){
cin>>a[i]>>b[i];
pos.push_back(a[i]);
pos.push_back(b[i]);
}
invfact[0]=1;
for(int i=1;i<=n;i++)invfact[i]=(invfact[i-1]*i)%mod;
for(int i=1;i<=n;i++)invfact[i]=power(invfact[i],mod-2);
sort(pos.begin(),pos.end());
for(int i=0;i<pos.size()-1;i++){
if(pos[i]!=pos[i+1]){
m++; s[m]={pos[i],pos[i]};
if(pos[i]+1<=pos[i+1]-1){
m++; s[m]={pos[i]+1,pos[i+1]-1};
}
}
}
m++;
s[m]={pos.back(),pos.back()};
for(int i=1;i<=m;i++){
cc[0][i]=1;
for(int f=1;f<=min(n,s[i].to-s[i].from+1);f++){
cc[f][i]=(long long) cc[f-1][i]*(s[i].to-s[i].from+1-(f-1));
cc[f][i]%=mod;
}
for(int f=1;f<=min(n,s[i].to-s[i].from+1);f++){
cc[f][i]*=invfact[f];
cc[f][i]%=mod;
}
}
for(int i=0;i<=m;i++){
for(int c=0;c<=n;c++){
if(i==0)dp[0][i][c][1]=1;
else dp[0][i][c][1]=comb(c,i);
}
}
for(int i=1;i<=n;i++){
dp[i%2][0][0][1]=1;
for(int f=1;f<=m;f++){
for(int c=0;c<=n;c++){
for(int t=0;t<2;t++){
dp[i%2][f][c][t]=dp[1-i%2][f][c][0];
if(t==1)dp[i%2][f][c][t]+=dp[i%2][f-1][0][1]*comb(c,f);
if(in(s[f],i) and c+1<=s[f].to-s[f].from+1){
dp[i%2][f][c][t]+=dp[1-i%2][f][c+1][1];
}
dp[i%2][f][c][t]%=mod;
}
}
}
}
cout<<(dp[n%2][m][0][1]-1+mod)%mod<<"\n";
return 0;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:60:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
60 | for(int i=0;i<pos.size()-1;i++){
| ~^~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
796 ms |
22104 KB |
Output is correct |
2 |
Correct |
839 ms |
22312 KB |
Output is correct |
3 |
Correct |
783 ms |
22104 KB |
Output is correct |
4 |
Correct |
780 ms |
22316 KB |
Output is correct |
5 |
Correct |
783 ms |
22312 KB |
Output is correct |
6 |
Correct |
801 ms |
22312 KB |
Output is correct |
7 |
Correct |
764 ms |
22316 KB |
Output is correct |
8 |
Correct |
800 ms |
22112 KB |
Output is correct |
9 |
Correct |
779 ms |
22108 KB |
Output is correct |
10 |
Correct |
789 ms |
22320 KB |
Output is correct |
11 |
Correct |
755 ms |
22104 KB |
Output is correct |
12 |
Correct |
773 ms |
22104 KB |
Output is correct |
13 |
Correct |
803 ms |
22312 KB |
Output is correct |
14 |
Correct |
788 ms |
22108 KB |
Output is correct |
15 |
Correct |
793 ms |
22316 KB |
Output is correct |
16 |
Correct |
135 ms |
6000 KB |
Output is correct |
17 |
Correct |
140 ms |
6236 KB |
Output is correct |
18 |
Correct |
133 ms |
5980 KB |
Output is correct |
19 |
Correct |
142 ms |
6236 KB |
Output is correct |
20 |
Correct |
135 ms |
6228 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
796 ms |
22104 KB |
Output is correct |
2 |
Correct |
839 ms |
22312 KB |
Output is correct |
3 |
Correct |
783 ms |
22104 KB |
Output is correct |
4 |
Correct |
780 ms |
22316 KB |
Output is correct |
5 |
Correct |
783 ms |
22312 KB |
Output is correct |
6 |
Correct |
801 ms |
22312 KB |
Output is correct |
7 |
Correct |
764 ms |
22316 KB |
Output is correct |
8 |
Correct |
800 ms |
22112 KB |
Output is correct |
9 |
Correct |
779 ms |
22108 KB |
Output is correct |
10 |
Correct |
789 ms |
22320 KB |
Output is correct |
11 |
Correct |
755 ms |
22104 KB |
Output is correct |
12 |
Correct |
773 ms |
22104 KB |
Output is correct |
13 |
Correct |
803 ms |
22312 KB |
Output is correct |
14 |
Correct |
788 ms |
22108 KB |
Output is correct |
15 |
Correct |
793 ms |
22316 KB |
Output is correct |
16 |
Correct |
135 ms |
6000 KB |
Output is correct |
17 |
Correct |
140 ms |
6236 KB |
Output is correct |
18 |
Correct |
133 ms |
5980 KB |
Output is correct |
19 |
Correct |
142 ms |
6236 KB |
Output is correct |
20 |
Correct |
135 ms |
6228 KB |
Output is correct |
21 |
Incorrect |
1278 ms |
29388 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
18 ms |
5464 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
796 ms |
22104 KB |
Output is correct |
2 |
Correct |
839 ms |
22312 KB |
Output is correct |
3 |
Correct |
783 ms |
22104 KB |
Output is correct |
4 |
Correct |
780 ms |
22316 KB |
Output is correct |
5 |
Correct |
783 ms |
22312 KB |
Output is correct |
6 |
Correct |
801 ms |
22312 KB |
Output is correct |
7 |
Correct |
764 ms |
22316 KB |
Output is correct |
8 |
Correct |
800 ms |
22112 KB |
Output is correct |
9 |
Correct |
779 ms |
22108 KB |
Output is correct |
10 |
Correct |
789 ms |
22320 KB |
Output is correct |
11 |
Correct |
755 ms |
22104 KB |
Output is correct |
12 |
Correct |
773 ms |
22104 KB |
Output is correct |
13 |
Correct |
803 ms |
22312 KB |
Output is correct |
14 |
Correct |
788 ms |
22108 KB |
Output is correct |
15 |
Correct |
793 ms |
22316 KB |
Output is correct |
16 |
Correct |
135 ms |
6000 KB |
Output is correct |
17 |
Correct |
140 ms |
6236 KB |
Output is correct |
18 |
Correct |
133 ms |
5980 KB |
Output is correct |
19 |
Correct |
142 ms |
6236 KB |
Output is correct |
20 |
Correct |
135 ms |
6228 KB |
Output is correct |
21 |
Incorrect |
1278 ms |
29388 KB |
Output isn't correct |
22 |
Halted |
0 ms |
0 KB |
- |