#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod=1e9+7;
ll n,c[1001],st[501],ed[501],cnt,comb[501];
ll dp[501][1001];
set<int> ss;
ll power(ll a, ll m) { //a^m;
ll ans=1;
while (m) {
if (m%2==1) ans=(ans*a)%mod;
a=(a*a)%mod;
m/=2;
}
return ans;
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin>>n;
for (int i=1; i<=n; ++i) {
cin>>st[i]>>ed[i]; --st[i];
ss.insert(st[i]);
ss.insert(ed[i]);
}
for (int i=1; i<=n; ++i) comb[i]=power(i,mod-2)%mod;
cnt=ss.size()-1;
int id=0;
for (auto it=ss.begin(); it!=ss.end(); ++it) c[id++]=*it;
for (int i=0; i<=cnt; ++i) dp[0][i]=1;
for (int i=1; i<=n; ++i) {
dp[i][0]=1; //don't send any boat
for (int j=1; j<=cnt; ++j) { //consider from the range from c[j-1]+1 to c[j]
dp[i][j]=dp[i][j-1];
ll idx=1,com=1;
for (auto k=i; k>0; --k) {
if (st[k]<c[j] && c[j]<=ed[k]) {
com=((com*(c[j]-c[j-1]+idx-1)%mod)*comb[idx])%mod;
dp[i][j]=(dp[i][j]+dp[k-1][j-1]*com)%mod;
++idx;
}
}
}
}
cout<<(dp[n][cnt]-1+mod)%mod;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
229 ms |
4260 KB |
Output is correct |
2 |
Correct |
245 ms |
4384 KB |
Output is correct |
3 |
Correct |
219 ms |
4172 KB |
Output is correct |
4 |
Correct |
227 ms |
4204 KB |
Output is correct |
5 |
Correct |
227 ms |
4172 KB |
Output is correct |
6 |
Correct |
137 ms |
4264 KB |
Output is correct |
7 |
Correct |
142 ms |
4172 KB |
Output is correct |
8 |
Correct |
164 ms |
4176 KB |
Output is correct |
9 |
Correct |
143 ms |
4248 KB |
Output is correct |
10 |
Correct |
141 ms |
4280 KB |
Output is correct |
11 |
Correct |
147 ms |
4252 KB |
Output is correct |
12 |
Correct |
142 ms |
4284 KB |
Output is correct |
13 |
Correct |
144 ms |
4300 KB |
Output is correct |
14 |
Correct |
134 ms |
4296 KB |
Output is correct |
15 |
Correct |
146 ms |
4280 KB |
Output is correct |
16 |
Correct |
50 ms |
3012 KB |
Output is correct |
17 |
Correct |
62 ms |
2980 KB |
Output is correct |
18 |
Correct |
55 ms |
3000 KB |
Output is correct |
19 |
Correct |
50 ms |
3048 KB |
Output is correct |
20 |
Correct |
51 ms |
3020 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
229 ms |
4260 KB |
Output is correct |
2 |
Correct |
245 ms |
4384 KB |
Output is correct |
3 |
Correct |
219 ms |
4172 KB |
Output is correct |
4 |
Correct |
227 ms |
4204 KB |
Output is correct |
5 |
Correct |
227 ms |
4172 KB |
Output is correct |
6 |
Correct |
137 ms |
4264 KB |
Output is correct |
7 |
Correct |
142 ms |
4172 KB |
Output is correct |
8 |
Correct |
164 ms |
4176 KB |
Output is correct |
9 |
Correct |
143 ms |
4248 KB |
Output is correct |
10 |
Correct |
141 ms |
4280 KB |
Output is correct |
11 |
Correct |
147 ms |
4252 KB |
Output is correct |
12 |
Correct |
142 ms |
4284 KB |
Output is correct |
13 |
Correct |
144 ms |
4300 KB |
Output is correct |
14 |
Correct |
134 ms |
4296 KB |
Output is correct |
15 |
Correct |
146 ms |
4280 KB |
Output is correct |
16 |
Correct |
50 ms |
3012 KB |
Output is correct |
17 |
Correct |
62 ms |
2980 KB |
Output is correct |
18 |
Correct |
55 ms |
3000 KB |
Output is correct |
19 |
Correct |
50 ms |
3048 KB |
Output is correct |
20 |
Correct |
51 ms |
3020 KB |
Output is correct |
21 |
Correct |
465 ms |
4296 KB |
Output is correct |
22 |
Correct |
473 ms |
4256 KB |
Output is correct |
23 |
Correct |
434 ms |
4172 KB |
Output is correct |
24 |
Correct |
470 ms |
4300 KB |
Output is correct |
25 |
Correct |
469 ms |
4296 KB |
Output is correct |
26 |
Correct |
638 ms |
4404 KB |
Output is correct |
27 |
Correct |
670 ms |
4228 KB |
Output is correct |
28 |
Correct |
636 ms |
4288 KB |
Output is correct |
29 |
Correct |
640 ms |
4304 KB |
Output is correct |
30 |
Correct |
156 ms |
4172 KB |
Output is correct |
31 |
Correct |
136 ms |
4244 KB |
Output is correct |
32 |
Correct |
141 ms |
4392 KB |
Output is correct |
33 |
Correct |
139 ms |
4244 KB |
Output is correct |
34 |
Correct |
154 ms |
4288 KB |
Output is correct |
35 |
Correct |
235 ms |
4228 KB |
Output is correct |
36 |
Correct |
238 ms |
4248 KB |
Output is correct |
37 |
Correct |
244 ms |
4184 KB |
Output is correct |
38 |
Correct |
233 ms |
4252 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
816 KB |
Output is correct |
2 |
Correct |
4 ms |
852 KB |
Output is correct |
3 |
Correct |
4 ms |
852 KB |
Output is correct |
4 |
Correct |
5 ms |
852 KB |
Output is correct |
5 |
Correct |
5 ms |
852 KB |
Output is correct |
6 |
Correct |
8 ms |
876 KB |
Output is correct |
7 |
Correct |
7 ms |
852 KB |
Output is correct |
8 |
Correct |
7 ms |
852 KB |
Output is correct |
9 |
Correct |
8 ms |
852 KB |
Output is correct |
10 |
Correct |
6 ms |
852 KB |
Output is correct |
11 |
Correct |
5 ms |
852 KB |
Output is correct |
12 |
Correct |
5 ms |
860 KB |
Output is correct |
13 |
Correct |
6 ms |
852 KB |
Output is correct |
14 |
Correct |
5 ms |
852 KB |
Output is correct |
15 |
Correct |
6 ms |
892 KB |
Output is correct |
16 |
Correct |
3 ms |
724 KB |
Output is correct |
17 |
Correct |
4 ms |
724 KB |
Output is correct |
18 |
Correct |
3 ms |
724 KB |
Output is correct |
19 |
Correct |
4 ms |
852 KB |
Output is correct |
20 |
Correct |
5 ms |
724 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
229 ms |
4260 KB |
Output is correct |
2 |
Correct |
245 ms |
4384 KB |
Output is correct |
3 |
Correct |
219 ms |
4172 KB |
Output is correct |
4 |
Correct |
227 ms |
4204 KB |
Output is correct |
5 |
Correct |
227 ms |
4172 KB |
Output is correct |
6 |
Correct |
137 ms |
4264 KB |
Output is correct |
7 |
Correct |
142 ms |
4172 KB |
Output is correct |
8 |
Correct |
164 ms |
4176 KB |
Output is correct |
9 |
Correct |
143 ms |
4248 KB |
Output is correct |
10 |
Correct |
141 ms |
4280 KB |
Output is correct |
11 |
Correct |
147 ms |
4252 KB |
Output is correct |
12 |
Correct |
142 ms |
4284 KB |
Output is correct |
13 |
Correct |
144 ms |
4300 KB |
Output is correct |
14 |
Correct |
134 ms |
4296 KB |
Output is correct |
15 |
Correct |
146 ms |
4280 KB |
Output is correct |
16 |
Correct |
50 ms |
3012 KB |
Output is correct |
17 |
Correct |
62 ms |
2980 KB |
Output is correct |
18 |
Correct |
55 ms |
3000 KB |
Output is correct |
19 |
Correct |
50 ms |
3048 KB |
Output is correct |
20 |
Correct |
51 ms |
3020 KB |
Output is correct |
21 |
Correct |
465 ms |
4296 KB |
Output is correct |
22 |
Correct |
473 ms |
4256 KB |
Output is correct |
23 |
Correct |
434 ms |
4172 KB |
Output is correct |
24 |
Correct |
470 ms |
4300 KB |
Output is correct |
25 |
Correct |
469 ms |
4296 KB |
Output is correct |
26 |
Correct |
638 ms |
4404 KB |
Output is correct |
27 |
Correct |
670 ms |
4228 KB |
Output is correct |
28 |
Correct |
636 ms |
4288 KB |
Output is correct |
29 |
Correct |
640 ms |
4304 KB |
Output is correct |
30 |
Correct |
156 ms |
4172 KB |
Output is correct |
31 |
Correct |
136 ms |
4244 KB |
Output is correct |
32 |
Correct |
141 ms |
4392 KB |
Output is correct |
33 |
Correct |
139 ms |
4244 KB |
Output is correct |
34 |
Correct |
154 ms |
4288 KB |
Output is correct |
35 |
Correct |
235 ms |
4228 KB |
Output is correct |
36 |
Correct |
238 ms |
4248 KB |
Output is correct |
37 |
Correct |
244 ms |
4184 KB |
Output is correct |
38 |
Correct |
233 ms |
4252 KB |
Output is correct |
39 |
Correct |
5 ms |
816 KB |
Output is correct |
40 |
Correct |
4 ms |
852 KB |
Output is correct |
41 |
Correct |
4 ms |
852 KB |
Output is correct |
42 |
Correct |
5 ms |
852 KB |
Output is correct |
43 |
Correct |
5 ms |
852 KB |
Output is correct |
44 |
Correct |
8 ms |
876 KB |
Output is correct |
45 |
Correct |
7 ms |
852 KB |
Output is correct |
46 |
Correct |
7 ms |
852 KB |
Output is correct |
47 |
Correct |
8 ms |
852 KB |
Output is correct |
48 |
Correct |
6 ms |
852 KB |
Output is correct |
49 |
Correct |
5 ms |
852 KB |
Output is correct |
50 |
Correct |
5 ms |
860 KB |
Output is correct |
51 |
Correct |
6 ms |
852 KB |
Output is correct |
52 |
Correct |
5 ms |
852 KB |
Output is correct |
53 |
Correct |
6 ms |
892 KB |
Output is correct |
54 |
Correct |
3 ms |
724 KB |
Output is correct |
55 |
Correct |
4 ms |
724 KB |
Output is correct |
56 |
Correct |
3 ms |
724 KB |
Output is correct |
57 |
Correct |
4 ms |
852 KB |
Output is correct |
58 |
Correct |
5 ms |
724 KB |
Output is correct |
59 |
Correct |
516 ms |
4288 KB |
Output is correct |
60 |
Correct |
502 ms |
4212 KB |
Output is correct |
61 |
Correct |
487 ms |
4280 KB |
Output is correct |
62 |
Correct |
520 ms |
4356 KB |
Output is correct |
63 |
Correct |
531 ms |
4428 KB |
Output is correct |
64 |
Correct |
750 ms |
4384 KB |
Output is correct |
65 |
Correct |
738 ms |
4368 KB |
Output is correct |
66 |
Correct |
739 ms |
4188 KB |
Output is correct |
67 |
Correct |
732 ms |
4312 KB |
Output is correct |
68 |
Correct |
750 ms |
4288 KB |
Output is correct |
69 |
Correct |
574 ms |
4384 KB |
Output is correct |
70 |
Correct |
587 ms |
4200 KB |
Output is correct |
71 |
Correct |
575 ms |
4244 KB |
Output is correct |
72 |
Correct |
635 ms |
4248 KB |
Output is correct |
73 |
Correct |
572 ms |
4312 KB |
Output is correct |
74 |
Correct |
108 ms |
2940 KB |
Output is correct |
75 |
Correct |
108 ms |
3004 KB |
Output is correct |
76 |
Correct |
102 ms |
3016 KB |
Output is correct |
77 |
Correct |
108 ms |
3040 KB |
Output is correct |
78 |
Correct |
99 ms |
3028 KB |
Output is correct |