#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define endl '\n'
const int mod = 1e9 + 7;
int add(int a,int b){
return (a + b >= mod ? a + b - mod : a + b);
}
int sub(int a,int b){
return (a - b >= 0 ? a - b : a - b + mod);
}
int mult(ll a,ll b){
return (a*b)%mod;
}
int power(int a,int b){
if(b == 0) return 1;
if(b == 1) return a;
int r = power(a,b/2);
if(b&1) return mult(mult(r,r),a);
return mult(r,r);
}
int divide(int a,int b){
return mult(a , power(b,mod-2));
}
int dp[1005][505];
void solve(){
int n;
cin>>n;
vector<int> a(n),b(n);
vector<int> v;
for(int i=0;i<n;i++){
cin>>a[i]>>b[i];
v.push_back(a[i]);
v.push_back(b[i]+1);
}
sort(v.begin(),v.end());
v.erase(unique(v.begin(),v.end()) , v.end());
int new_n = v.size();
vector<vector<int>> idx(new_n+1);
for(int i=0;i<n;i++){
int l = lower_bound(v.begin(),v.end(),a[i]) - v.begin();
int r = upper_bound(v.begin(),v.end(),b[i]) - v.begin();
for(int j=l;j<r;j++){
idx[j].push_back(i+1);
}
}
vector<int> inv(n+1);
for(int i=1;i<=n;i++) inv[i] = divide(1,i);
for(int i=1;i<=n;i++) dp[new_n][i] = 1;
for(int j=new_n-1;j>=0;j--){
int sz = idx[j].size();
vector<vector<int>> dp2(sz+1,vector<int>(sz+1));
for(int i=sz-1;i>=0;i--){
for(int k=1;k<=sz;k++){
if(k == 1) dp2[i][k] = add(dp2[i][k] , dp[j+1][idx[j][i]]);
else dp2[i][k] = add(dp2[i][k] , dp2[i+1][k-1]);
dp2[i][k] = add(dp2[i][k] , dp2[i+1][k]);
}
}
for(int i=0;i<=n;i++){
int gap = (j < new_n - 1 ? v[j+1] - v[j] : 0);
sz = min(sz , gap);
int x = 1;
int st = upper_bound(idx[j].begin(),idx[j].end(),i) - idx[j].begin();
dp[j][i] = dp[j+1][i];
for(int k=1;k<=sz;k++){
x = mult(x , gap-k+1);
x = mult(x , inv[k]);
dp[j][i] = add(dp[j][i],mult(dp2[st][k],x));
}
}
}
cout<<dp[0][0]<<endl;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int t=1;
//cin>>t;
while(t--){
solve();
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
2392 KB |
Output is correct |
2 |
Correct |
4 ms |
2396 KB |
Output is correct |
3 |
Correct |
3 ms |
2396 KB |
Output is correct |
4 |
Correct |
3 ms |
2396 KB |
Output is correct |
5 |
Correct |
3 ms |
2396 KB |
Output is correct |
6 |
Correct |
3 ms |
2268 KB |
Output is correct |
7 |
Correct |
3 ms |
2396 KB |
Output is correct |
8 |
Correct |
3 ms |
2396 KB |
Output is correct |
9 |
Correct |
4 ms |
2268 KB |
Output is correct |
10 |
Correct |
3 ms |
2396 KB |
Output is correct |
11 |
Correct |
3 ms |
2396 KB |
Output is correct |
12 |
Correct |
3 ms |
2396 KB |
Output is correct |
13 |
Correct |
3 ms |
2396 KB |
Output is correct |
14 |
Correct |
3 ms |
2396 KB |
Output is correct |
15 |
Correct |
3 ms |
2388 KB |
Output is correct |
16 |
Correct |
1 ms |
604 KB |
Output is correct |
17 |
Correct |
1 ms |
860 KB |
Output is correct |
18 |
Correct |
1 ms |
748 KB |
Output is correct |
19 |
Correct |
1 ms |
860 KB |
Output is correct |
20 |
Correct |
1 ms |
860 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
2392 KB |
Output is correct |
2 |
Correct |
4 ms |
2396 KB |
Output is correct |
3 |
Correct |
3 ms |
2396 KB |
Output is correct |
4 |
Correct |
3 ms |
2396 KB |
Output is correct |
5 |
Correct |
3 ms |
2396 KB |
Output is correct |
6 |
Correct |
3 ms |
2268 KB |
Output is correct |
7 |
Correct |
3 ms |
2396 KB |
Output is correct |
8 |
Correct |
3 ms |
2396 KB |
Output is correct |
9 |
Correct |
4 ms |
2268 KB |
Output is correct |
10 |
Correct |
3 ms |
2396 KB |
Output is correct |
11 |
Correct |
3 ms |
2396 KB |
Output is correct |
12 |
Correct |
3 ms |
2396 KB |
Output is correct |
13 |
Correct |
3 ms |
2396 KB |
Output is correct |
14 |
Correct |
3 ms |
2396 KB |
Output is correct |
15 |
Correct |
3 ms |
2388 KB |
Output is correct |
16 |
Correct |
1 ms |
604 KB |
Output is correct |
17 |
Correct |
1 ms |
860 KB |
Output is correct |
18 |
Correct |
1 ms |
748 KB |
Output is correct |
19 |
Correct |
1 ms |
860 KB |
Output is correct |
20 |
Correct |
1 ms |
860 KB |
Output is correct |
21 |
Correct |
80 ms |
3496 KB |
Output is correct |
22 |
Correct |
76 ms |
3512 KB |
Output is correct |
23 |
Correct |
72 ms |
3284 KB |
Output is correct |
24 |
Correct |
76 ms |
3324 KB |
Output is correct |
25 |
Correct |
78 ms |
3392 KB |
Output is correct |
26 |
Correct |
158 ms |
3984 KB |
Output is correct |
27 |
Correct |
165 ms |
4016 KB |
Output is correct |
28 |
Correct |
157 ms |
4000 KB |
Output is correct |
29 |
Correct |
152 ms |
3864 KB |
Output is correct |
30 |
Correct |
6 ms |
2396 KB |
Output is correct |
31 |
Correct |
6 ms |
2400 KB |
Output is correct |
32 |
Correct |
6 ms |
2396 KB |
Output is correct |
33 |
Correct |
6 ms |
2396 KB |
Output is correct |
34 |
Correct |
6 ms |
2400 KB |
Output is correct |
35 |
Correct |
5 ms |
2396 KB |
Output is correct |
36 |
Correct |
5 ms |
2396 KB |
Output is correct |
37 |
Correct |
4 ms |
2396 KB |
Output is correct |
38 |
Correct |
4 ms |
2480 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
7 ms |
860 KB |
Output is correct |
2 |
Correct |
6 ms |
860 KB |
Output is correct |
3 |
Correct |
6 ms |
860 KB |
Output is correct |
4 |
Correct |
6 ms |
860 KB |
Output is correct |
5 |
Correct |
7 ms |
860 KB |
Output is correct |
6 |
Correct |
10 ms |
860 KB |
Output is correct |
7 |
Correct |
10 ms |
912 KB |
Output is correct |
8 |
Correct |
10 ms |
1020 KB |
Output is correct |
9 |
Correct |
12 ms |
884 KB |
Output is correct |
10 |
Correct |
11 ms |
860 KB |
Output is correct |
11 |
Correct |
7 ms |
860 KB |
Output is correct |
12 |
Correct |
6 ms |
860 KB |
Output is correct |
13 |
Correct |
8 ms |
860 KB |
Output is correct |
14 |
Correct |
8 ms |
860 KB |
Output is correct |
15 |
Correct |
7 ms |
860 KB |
Output is correct |
16 |
Correct |
3 ms |
600 KB |
Output is correct |
17 |
Correct |
3 ms |
604 KB |
Output is correct |
18 |
Correct |
3 ms |
604 KB |
Output is correct |
19 |
Correct |
3 ms |
604 KB |
Output is correct |
20 |
Correct |
3 ms |
604 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
2392 KB |
Output is correct |
2 |
Correct |
4 ms |
2396 KB |
Output is correct |
3 |
Correct |
3 ms |
2396 KB |
Output is correct |
4 |
Correct |
3 ms |
2396 KB |
Output is correct |
5 |
Correct |
3 ms |
2396 KB |
Output is correct |
6 |
Correct |
3 ms |
2268 KB |
Output is correct |
7 |
Correct |
3 ms |
2396 KB |
Output is correct |
8 |
Correct |
3 ms |
2396 KB |
Output is correct |
9 |
Correct |
4 ms |
2268 KB |
Output is correct |
10 |
Correct |
3 ms |
2396 KB |
Output is correct |
11 |
Correct |
3 ms |
2396 KB |
Output is correct |
12 |
Correct |
3 ms |
2396 KB |
Output is correct |
13 |
Correct |
3 ms |
2396 KB |
Output is correct |
14 |
Correct |
3 ms |
2396 KB |
Output is correct |
15 |
Correct |
3 ms |
2388 KB |
Output is correct |
16 |
Correct |
1 ms |
604 KB |
Output is correct |
17 |
Correct |
1 ms |
860 KB |
Output is correct |
18 |
Correct |
1 ms |
748 KB |
Output is correct |
19 |
Correct |
1 ms |
860 KB |
Output is correct |
20 |
Correct |
1 ms |
860 KB |
Output is correct |
21 |
Correct |
80 ms |
3496 KB |
Output is correct |
22 |
Correct |
76 ms |
3512 KB |
Output is correct |
23 |
Correct |
72 ms |
3284 KB |
Output is correct |
24 |
Correct |
76 ms |
3324 KB |
Output is correct |
25 |
Correct |
78 ms |
3392 KB |
Output is correct |
26 |
Correct |
158 ms |
3984 KB |
Output is correct |
27 |
Correct |
165 ms |
4016 KB |
Output is correct |
28 |
Correct |
157 ms |
4000 KB |
Output is correct |
29 |
Correct |
152 ms |
3864 KB |
Output is correct |
30 |
Correct |
6 ms |
2396 KB |
Output is correct |
31 |
Correct |
6 ms |
2400 KB |
Output is correct |
32 |
Correct |
6 ms |
2396 KB |
Output is correct |
33 |
Correct |
6 ms |
2396 KB |
Output is correct |
34 |
Correct |
6 ms |
2400 KB |
Output is correct |
35 |
Correct |
5 ms |
2396 KB |
Output is correct |
36 |
Correct |
5 ms |
2396 KB |
Output is correct |
37 |
Correct |
4 ms |
2396 KB |
Output is correct |
38 |
Correct |
4 ms |
2480 KB |
Output is correct |
39 |
Correct |
7 ms |
860 KB |
Output is correct |
40 |
Correct |
6 ms |
860 KB |
Output is correct |
41 |
Correct |
6 ms |
860 KB |
Output is correct |
42 |
Correct |
6 ms |
860 KB |
Output is correct |
43 |
Correct |
7 ms |
860 KB |
Output is correct |
44 |
Correct |
10 ms |
860 KB |
Output is correct |
45 |
Correct |
10 ms |
912 KB |
Output is correct |
46 |
Correct |
10 ms |
1020 KB |
Output is correct |
47 |
Correct |
12 ms |
884 KB |
Output is correct |
48 |
Correct |
11 ms |
860 KB |
Output is correct |
49 |
Correct |
7 ms |
860 KB |
Output is correct |
50 |
Correct |
6 ms |
860 KB |
Output is correct |
51 |
Correct |
8 ms |
860 KB |
Output is correct |
52 |
Correct |
8 ms |
860 KB |
Output is correct |
53 |
Correct |
7 ms |
860 KB |
Output is correct |
54 |
Correct |
3 ms |
600 KB |
Output is correct |
55 |
Correct |
3 ms |
604 KB |
Output is correct |
56 |
Correct |
3 ms |
604 KB |
Output is correct |
57 |
Correct |
3 ms |
604 KB |
Output is correct |
58 |
Correct |
3 ms |
604 KB |
Output is correct |
59 |
Correct |
780 ms |
3728 KB |
Output is correct |
60 |
Correct |
741 ms |
3496 KB |
Output is correct |
61 |
Correct |
715 ms |
3492 KB |
Output is correct |
62 |
Correct |
793 ms |
3672 KB |
Output is correct |
63 |
Correct |
763 ms |
3524 KB |
Output is correct |
64 |
Correct |
1207 ms |
4152 KB |
Output is correct |
65 |
Correct |
1229 ms |
4312 KB |
Output is correct |
66 |
Correct |
1217 ms |
4232 KB |
Output is correct |
67 |
Correct |
1241 ms |
4184 KB |
Output is correct |
68 |
Correct |
1201 ms |
4064 KB |
Output is correct |
69 |
Correct |
719 ms |
3528 KB |
Output is correct |
70 |
Correct |
729 ms |
3776 KB |
Output is correct |
71 |
Correct |
731 ms |
3588 KB |
Output is correct |
72 |
Correct |
743 ms |
3508 KB |
Output is correct |
73 |
Correct |
747 ms |
3468 KB |
Output is correct |
74 |
Correct |
85 ms |
1292 KB |
Output is correct |
75 |
Correct |
85 ms |
1304 KB |
Output is correct |
76 |
Correct |
89 ms |
1296 KB |
Output is correct |
77 |
Correct |
86 ms |
1316 KB |
Output is correct |
78 |
Correct |
85 ms |
1368 KB |
Output is correct |