#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
//template
#define rep(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define ALL(v) (v).begin(),(v).end()
typedef long long int ll;
const int inf = 0x3fffffff; const ll INF = 0x1fffffffffffffff; const double eps=1e-12;
template<typename T>inline bool chmax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
template<typename T>inline bool chmin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
//end
template<unsigned mod=1000000007>struct fp {
int v; static unsigned get_mod(){return mod;}
int inv() const{
int tmp,a=v,b=mod,x=1,y=0;
while(b)tmp=a/b,a-=tmp*b,swap(a,b),x-=tmp*y,swap(x,y);
if(x<0){x+=mod;} return x;
}
fp():v(0){}
fp(ll x):v(x>=0?x%mod:mod+(x%mod)){}
fp operator-()const{return fp(-v);}
fp pow(ll t){fp res=1,b=*this; while(t){if(t&1)res*=b;b*=b;t>>=1;} return res;}
fp& operator+=(const fp& x){if((v+=x.v)>=(int)mod)v-=mod; return *this;}
fp& operator-=(const fp& x){if((v+=mod-x.v)>=(int)mod)v-=mod; return *this;}
fp& operator*=(const fp& x){v=ll(v)*x.v%mod; return *this;}
fp& operator/=(const fp& x){v=ll(v)*x.inv()%mod; return *this;}
fp operator+(const fp& x)const{return fp(*this)+=x;}
fp operator-(const fp& x)const{return fp(*this)-=x;}
fp operator*(const fp& x)const{return fp(*this)*=x;}
fp operator/(const fp& x)const{return fp(*this)/=x;}
bool operator==(const fp& x)const{return v==x.v;}
bool operator!=(const fp& x)const{return v!=x.v;}
}; using Fp=fp<>;
template<typename T>struct factorial {
vector<T> Fact,Finv,Inv;
factorial(int maxx){
Fact.resize(maxx); Finv.resize(maxx); Inv.resize(maxx);
Fact[0]=Fact[1]=Finv[0]=Finv[1]=Inv[1]=1;
rep(i,2,maxx){Fact[i]=Fact[i-1]*i;} Finv[maxx-1]=Fact[maxx-1].inv();
for(int i=maxx-1;i>=2;i--){Finv[i-1]=Finv[i]*i; Inv[i]=Finv[i]*Fact[i-1];}
}
T fact(int n,bool inv=0){if(inv)return Finv[n];else return Fact[n];}
T inv(int n){return Inv[n];}
T nPr(int n,int r){if(n<0||n<r||r<0)return Fp(0);else return Fact[n]*Finv[n-r];}
T nCr(int n,int r){if(n<0||n<r||r<0)return Fp(0);else return Fact[n]*Finv[r]*Finv[n-r];}
};
Fp dp[510][1010],c[1010][510]; factorial<Fp> fact(1010);
int main(){
int n; cin>>n;
vector<int> a(n),b(n),vs={0,inf};
rep(i,0,n){
cin>>a[i]>>b[i]; b[i]++;
vs.push_back(a[i]);
vs.push_back(b[i]);
}
sort(ALL(vs)); vs.erase(unique(ALL(vs)),vs.end());
int m=vs.size();
rep(i,0,n){
a[i]=lower_bound(ALL(vs),a[i])-vs.begin();
b[i]=lower_bound(ALL(vs),b[i])-vs.begin();
}
//precalc
rep(i,0,m-1){
c[i][0]=1;
rep(j,0,n)c[i][j+1]=c[i][j]*(vs[i+1]-vs[i]+j)*fact.inv(j+1);
}
Fp res;
rep(i,0,n){
rep(j,a[i],b[i]){
int cnt=0;
for(int k=i;k;k--){
if(a[k]<=j and j<b[k])cnt++;
dp[i][j+1]+=dp[k-1][j]*c[j][cnt];
}
if(a[0]<=j and j<b[0])cnt++;
dp[i][j+1]+=c[j][cnt];
}
rep(j,0,m-1)dp[i][j+1]+=dp[i][j];
res+=dp[i][m-1];
}
cout<<res.v<<endl;
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
4352 KB |
Output is correct |
2 |
Correct |
13 ms |
4352 KB |
Output is correct |
3 |
Correct |
13 ms |
4352 KB |
Output is correct |
4 |
Correct |
13 ms |
4352 KB |
Output is correct |
5 |
Correct |
13 ms |
4352 KB |
Output is correct |
6 |
Correct |
13 ms |
4352 KB |
Output is correct |
7 |
Correct |
13 ms |
4480 KB |
Output is correct |
8 |
Correct |
13 ms |
4352 KB |
Output is correct |
9 |
Correct |
13 ms |
4352 KB |
Output is correct |
10 |
Correct |
13 ms |
4352 KB |
Output is correct |
11 |
Correct |
13 ms |
4352 KB |
Output is correct |
12 |
Correct |
14 ms |
4352 KB |
Output is correct |
13 |
Correct |
13 ms |
4352 KB |
Output is correct |
14 |
Correct |
13 ms |
4352 KB |
Output is correct |
15 |
Correct |
12 ms |
4352 KB |
Output is correct |
16 |
Correct |
6 ms |
4352 KB |
Output is correct |
17 |
Correct |
6 ms |
4352 KB |
Output is correct |
18 |
Correct |
6 ms |
4352 KB |
Output is correct |
19 |
Correct |
6 ms |
4352 KB |
Output is correct |
20 |
Correct |
6 ms |
4352 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
4352 KB |
Output is correct |
2 |
Correct |
13 ms |
4352 KB |
Output is correct |
3 |
Correct |
13 ms |
4352 KB |
Output is correct |
4 |
Correct |
13 ms |
4352 KB |
Output is correct |
5 |
Correct |
13 ms |
4352 KB |
Output is correct |
6 |
Correct |
13 ms |
4352 KB |
Output is correct |
7 |
Correct |
13 ms |
4480 KB |
Output is correct |
8 |
Correct |
13 ms |
4352 KB |
Output is correct |
9 |
Correct |
13 ms |
4352 KB |
Output is correct |
10 |
Correct |
13 ms |
4352 KB |
Output is correct |
11 |
Correct |
13 ms |
4352 KB |
Output is correct |
12 |
Correct |
14 ms |
4352 KB |
Output is correct |
13 |
Correct |
13 ms |
4352 KB |
Output is correct |
14 |
Correct |
13 ms |
4352 KB |
Output is correct |
15 |
Correct |
12 ms |
4352 KB |
Output is correct |
16 |
Correct |
6 ms |
4352 KB |
Output is correct |
17 |
Correct |
6 ms |
4352 KB |
Output is correct |
18 |
Correct |
6 ms |
4352 KB |
Output is correct |
19 |
Correct |
6 ms |
4352 KB |
Output is correct |
20 |
Correct |
6 ms |
4352 KB |
Output is correct |
21 |
Correct |
400 ms |
4472 KB |
Output is correct |
22 |
Correct |
384 ms |
4424 KB |
Output is correct |
23 |
Correct |
366 ms |
4472 KB |
Output is correct |
24 |
Correct |
390 ms |
4352 KB |
Output is correct |
25 |
Correct |
386 ms |
4472 KB |
Output is correct |
26 |
Correct |
534 ms |
4472 KB |
Output is correct |
27 |
Correct |
541 ms |
4352 KB |
Output is correct |
28 |
Correct |
532 ms |
4472 KB |
Output is correct |
29 |
Correct |
530 ms |
4472 KB |
Output is correct |
30 |
Correct |
16 ms |
4472 KB |
Output is correct |
31 |
Correct |
15 ms |
4352 KB |
Output is correct |
32 |
Correct |
15 ms |
4352 KB |
Output is correct |
33 |
Correct |
15 ms |
4352 KB |
Output is correct |
34 |
Correct |
15 ms |
4352 KB |
Output is correct |
35 |
Correct |
15 ms |
4352 KB |
Output is correct |
36 |
Correct |
15 ms |
4352 KB |
Output is correct |
37 |
Correct |
15 ms |
4352 KB |
Output is correct |
38 |
Correct |
18 ms |
4352 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
7 ms |
4352 KB |
Output is correct |
2 |
Correct |
7 ms |
4352 KB |
Output is correct |
3 |
Correct |
8 ms |
4352 KB |
Output is correct |
4 |
Correct |
7 ms |
4352 KB |
Output is correct |
5 |
Correct |
8 ms |
4352 KB |
Output is correct |
6 |
Correct |
10 ms |
4352 KB |
Output is correct |
7 |
Correct |
10 ms |
4352 KB |
Output is correct |
8 |
Correct |
8 ms |
4352 KB |
Output is correct |
9 |
Correct |
11 ms |
4352 KB |
Output is correct |
10 |
Correct |
8 ms |
4352 KB |
Output is correct |
11 |
Correct |
6 ms |
4352 KB |
Output is correct |
12 |
Correct |
6 ms |
4352 KB |
Output is correct |
13 |
Correct |
6 ms |
4352 KB |
Output is correct |
14 |
Correct |
7 ms |
4352 KB |
Output is correct |
15 |
Correct |
6 ms |
4352 KB |
Output is correct |
16 |
Correct |
5 ms |
4352 KB |
Output is correct |
17 |
Correct |
5 ms |
4352 KB |
Output is correct |
18 |
Correct |
6 ms |
4352 KB |
Output is correct |
19 |
Correct |
7 ms |
4352 KB |
Output is correct |
20 |
Correct |
6 ms |
4352 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
4352 KB |
Output is correct |
2 |
Correct |
13 ms |
4352 KB |
Output is correct |
3 |
Correct |
13 ms |
4352 KB |
Output is correct |
4 |
Correct |
13 ms |
4352 KB |
Output is correct |
5 |
Correct |
13 ms |
4352 KB |
Output is correct |
6 |
Correct |
13 ms |
4352 KB |
Output is correct |
7 |
Correct |
13 ms |
4480 KB |
Output is correct |
8 |
Correct |
13 ms |
4352 KB |
Output is correct |
9 |
Correct |
13 ms |
4352 KB |
Output is correct |
10 |
Correct |
13 ms |
4352 KB |
Output is correct |
11 |
Correct |
13 ms |
4352 KB |
Output is correct |
12 |
Correct |
14 ms |
4352 KB |
Output is correct |
13 |
Correct |
13 ms |
4352 KB |
Output is correct |
14 |
Correct |
13 ms |
4352 KB |
Output is correct |
15 |
Correct |
12 ms |
4352 KB |
Output is correct |
16 |
Correct |
6 ms |
4352 KB |
Output is correct |
17 |
Correct |
6 ms |
4352 KB |
Output is correct |
18 |
Correct |
6 ms |
4352 KB |
Output is correct |
19 |
Correct |
6 ms |
4352 KB |
Output is correct |
20 |
Correct |
6 ms |
4352 KB |
Output is correct |
21 |
Correct |
400 ms |
4472 KB |
Output is correct |
22 |
Correct |
384 ms |
4424 KB |
Output is correct |
23 |
Correct |
366 ms |
4472 KB |
Output is correct |
24 |
Correct |
390 ms |
4352 KB |
Output is correct |
25 |
Correct |
386 ms |
4472 KB |
Output is correct |
26 |
Correct |
534 ms |
4472 KB |
Output is correct |
27 |
Correct |
541 ms |
4352 KB |
Output is correct |
28 |
Correct |
532 ms |
4472 KB |
Output is correct |
29 |
Correct |
530 ms |
4472 KB |
Output is correct |
30 |
Correct |
16 ms |
4472 KB |
Output is correct |
31 |
Correct |
15 ms |
4352 KB |
Output is correct |
32 |
Correct |
15 ms |
4352 KB |
Output is correct |
33 |
Correct |
15 ms |
4352 KB |
Output is correct |
34 |
Correct |
15 ms |
4352 KB |
Output is correct |
35 |
Correct |
15 ms |
4352 KB |
Output is correct |
36 |
Correct |
15 ms |
4352 KB |
Output is correct |
37 |
Correct |
15 ms |
4352 KB |
Output is correct |
38 |
Correct |
18 ms |
4352 KB |
Output is correct |
39 |
Correct |
7 ms |
4352 KB |
Output is correct |
40 |
Correct |
7 ms |
4352 KB |
Output is correct |
41 |
Correct |
8 ms |
4352 KB |
Output is correct |
42 |
Correct |
7 ms |
4352 KB |
Output is correct |
43 |
Correct |
8 ms |
4352 KB |
Output is correct |
44 |
Correct |
10 ms |
4352 KB |
Output is correct |
45 |
Correct |
10 ms |
4352 KB |
Output is correct |
46 |
Correct |
8 ms |
4352 KB |
Output is correct |
47 |
Correct |
11 ms |
4352 KB |
Output is correct |
48 |
Correct |
8 ms |
4352 KB |
Output is correct |
49 |
Correct |
6 ms |
4352 KB |
Output is correct |
50 |
Correct |
6 ms |
4352 KB |
Output is correct |
51 |
Correct |
6 ms |
4352 KB |
Output is correct |
52 |
Correct |
7 ms |
4352 KB |
Output is correct |
53 |
Correct |
6 ms |
4352 KB |
Output is correct |
54 |
Correct |
5 ms |
4352 KB |
Output is correct |
55 |
Correct |
5 ms |
4352 KB |
Output is correct |
56 |
Correct |
6 ms |
4352 KB |
Output is correct |
57 |
Correct |
7 ms |
4352 KB |
Output is correct |
58 |
Correct |
6 ms |
4352 KB |
Output is correct |
59 |
Correct |
434 ms |
4432 KB |
Output is correct |
60 |
Correct |
413 ms |
4544 KB |
Output is correct |
61 |
Correct |
440 ms |
4428 KB |
Output is correct |
62 |
Correct |
433 ms |
4352 KB |
Output is correct |
63 |
Correct |
427 ms |
4500 KB |
Output is correct |
64 |
Correct |
629 ms |
4428 KB |
Output is correct |
65 |
Correct |
615 ms |
4472 KB |
Output is correct |
66 |
Correct |
607 ms |
4352 KB |
Output is correct |
67 |
Correct |
611 ms |
4552 KB |
Output is correct |
68 |
Correct |
608 ms |
4472 KB |
Output is correct |
69 |
Correct |
325 ms |
4352 KB |
Output is correct |
70 |
Correct |
318 ms |
4472 KB |
Output is correct |
71 |
Correct |
320 ms |
4352 KB |
Output is correct |
72 |
Correct |
330 ms |
4472 KB |
Output is correct |
73 |
Correct |
334 ms |
4352 KB |
Output is correct |
74 |
Correct |
84 ms |
4352 KB |
Output is correct |
75 |
Correct |
80 ms |
4352 KB |
Output is correct |
76 |
Correct |
85 ms |
4352 KB |
Output is correct |
77 |
Correct |
83 ms |
4352 KB |
Output is correct |
78 |
Correct |
88 ms |
4352 KB |
Output is correct |