#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int ll
typedef pair<int32_t, int32_t> pi;
typedef vector <int> vi;
typedef vector <pi> vpi;
typedef pair<pi, ll> pii;
typedef set <ll> si;
typedef long double ld;
#define f first
#define s second
#define mp make_pair
#define FOR(i,s,e) for(int i=s;i<=int(e);++i)
#define DEC(i,s,e) for(int i=s;i>=int(e);--i)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define lbd(x, y) lower_bound(all(x), y)
#define ubd(x, y) upper_bound(all(x), y)
#define aFOR(i,x) for (auto i: x)
#define mem(x,i) memset(x,i,sizeof x)
#define fast ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define maxn 510
#define INF (ll)1e9+10
#define MOD 1000000007
typedef pair <vi, int> pvi;
typedef pair <int,pi> ipi;
typedef vector <pii> vpii;
int N,A[maxn],B[maxn];
int fac[maxn], invfac[maxn];
int qexp(int a,int b){
int ans = 1;
while (b){
if (b&1) (ans *= a) %= MOD;
(a *= a) %= MOD;
b >>= 1;
}
return ans;
}
int nck(int n,int k){
if (k > n) return 0;
return (((fac[n] * invfac[k]) % MOD) * invfac[n-k]) % MOD;
}
int suffmult[4*maxn][maxn];
int dp[maxn][4*maxn];
int S[4*maxn],E[4*maxn];
int specnck(int x,int k){
//~ cout << E[x]-S[x]+1 << ' ' << k << ' ' << (invfac[k] * suffmult[x][k]) % MOD << '\n';
return (invfac[k] * suffmult[x][k]) % MOD;
}
int memo[maxn][4*maxn];
int f(int x,int y){
if (memo[x][y] != -1) return memo[x][y];
int ans = 0;
FOR(z,1,x){
(ans += (nck(x-1,z-1) * specnck(y,z)) % MOD) %= MOD;
}
return memo[x][y] = ans;
}
int32_t main(){
cin >> N;
FOR(i,1,N) cin >> A[i] >> B[i];
fac[0] = 1;
FOR(i,1,N) fac[i] = (fac[i-1] * i) % MOD;
invfac[N] = qexp(fac[N], MOD-2);
DEC(i,N-1,0) invfac[i] = (invfac[i+1] * (i+1)) % MOD;
vi v;
FOR(i,1,N){
v.pb(A[i]); v.pb(B[i]);
}
v.pb(0); v.pb(INF);
sort(all(v)); v.erase(unique(all(v)),v.end());
int M = 1;
FOR(i,0,(int)v.size()-1){
S[M] = v[i]; E[M] = v[i];
M++;
if (i + 1 < (int)v.size() && v[i] + 1 < v[i+1]){
S[M] = v[i]+1; E[M] = v[i+1]-1; M++;
}
}
M--;
FOR(i,1,M){
suffmult[i][0] = 1;
int x = E[i] - S[i] + 1;
FOR(j,1,N){
suffmult[i][j] = (suffmult[i][j-1] * x) % MOD;
x--;
}
}
FOR(i,1,M+1) dp[N+1][i] = 1;
mem(memo, -1);
DEC(i,N,1){
DEC(j,M,1){
if (B[i] < S[j]){
dp[i][j] = 0; continue;
}
dp[i][j] = dp[i][j+1];
if (A[i] <= S[j] && E[j] <= B[i]){
int num = 1;
FOR(k,i+1,N){
(dp[i][j] += (dp[k][j+1] * f(num, j)) % MOD) %= MOD;
if (A[k] <= S[j] && E[j] <= B[k]) num++;
}
(dp[i][j] += f(num, j)) %= MOD; // if no more > j segments
}
}
}
int ans = 0;
FOR(i,1,N){
(ans += dp[i][1]) %= MOD;
}
cout << ans;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
18352 KB |
Output is correct |
2 |
Correct |
13 ms |
18324 KB |
Output is correct |
3 |
Correct |
13 ms |
18436 KB |
Output is correct |
4 |
Correct |
14 ms |
18360 KB |
Output is correct |
5 |
Correct |
16 ms |
18364 KB |
Output is correct |
6 |
Correct |
15 ms |
18436 KB |
Output is correct |
7 |
Correct |
15 ms |
18356 KB |
Output is correct |
8 |
Correct |
13 ms |
18388 KB |
Output is correct |
9 |
Correct |
13 ms |
18364 KB |
Output is correct |
10 |
Correct |
13 ms |
18380 KB |
Output is correct |
11 |
Correct |
13 ms |
18428 KB |
Output is correct |
12 |
Correct |
13 ms |
18332 KB |
Output is correct |
13 |
Correct |
13 ms |
18388 KB |
Output is correct |
14 |
Correct |
12 ms |
18384 KB |
Output is correct |
15 |
Correct |
13 ms |
18388 KB |
Output is correct |
16 |
Correct |
7 ms |
11860 KB |
Output is correct |
17 |
Correct |
8 ms |
11988 KB |
Output is correct |
18 |
Correct |
8 ms |
11860 KB |
Output is correct |
19 |
Correct |
9 ms |
11988 KB |
Output is correct |
20 |
Correct |
7 ms |
11932 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
18352 KB |
Output is correct |
2 |
Correct |
13 ms |
18324 KB |
Output is correct |
3 |
Correct |
13 ms |
18436 KB |
Output is correct |
4 |
Correct |
14 ms |
18360 KB |
Output is correct |
5 |
Correct |
16 ms |
18364 KB |
Output is correct |
6 |
Correct |
15 ms |
18436 KB |
Output is correct |
7 |
Correct |
15 ms |
18356 KB |
Output is correct |
8 |
Correct |
13 ms |
18388 KB |
Output is correct |
9 |
Correct |
13 ms |
18364 KB |
Output is correct |
10 |
Correct |
13 ms |
18380 KB |
Output is correct |
11 |
Correct |
13 ms |
18428 KB |
Output is correct |
12 |
Correct |
13 ms |
18332 KB |
Output is correct |
13 |
Correct |
13 ms |
18388 KB |
Output is correct |
14 |
Correct |
12 ms |
18384 KB |
Output is correct |
15 |
Correct |
13 ms |
18388 KB |
Output is correct |
16 |
Correct |
7 ms |
11860 KB |
Output is correct |
17 |
Correct |
8 ms |
11988 KB |
Output is correct |
18 |
Correct |
8 ms |
11860 KB |
Output is correct |
19 |
Correct |
9 ms |
11988 KB |
Output is correct |
20 |
Correct |
7 ms |
11932 KB |
Output is correct |
21 |
Correct |
833 ms |
23176 KB |
Output is correct |
22 |
Correct |
824 ms |
23200 KB |
Output is correct |
23 |
Correct |
755 ms |
23116 KB |
Output is correct |
24 |
Correct |
811 ms |
23240 KB |
Output is correct |
25 |
Correct |
877 ms |
23052 KB |
Output is correct |
26 |
Correct |
1484 ms |
22816 KB |
Output is correct |
27 |
Correct |
1412 ms |
22732 KB |
Output is correct |
28 |
Correct |
1445 ms |
22704 KB |
Output is correct |
29 |
Correct |
1482 ms |
23004 KB |
Output is correct |
30 |
Correct |
28 ms |
23840 KB |
Output is correct |
31 |
Correct |
24 ms |
23804 KB |
Output is correct |
32 |
Correct |
21 ms |
23892 KB |
Output is correct |
33 |
Correct |
25 ms |
23824 KB |
Output is correct |
34 |
Correct |
21 ms |
23796 KB |
Output is correct |
35 |
Correct |
15 ms |
18388 KB |
Output is correct |
36 |
Correct |
15 ms |
18368 KB |
Output is correct |
37 |
Correct |
16 ms |
18388 KB |
Output is correct |
38 |
Correct |
17 ms |
18432 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
14 ms |
10724 KB |
Output is correct |
2 |
Correct |
12 ms |
10688 KB |
Output is correct |
3 |
Correct |
13 ms |
10708 KB |
Output is correct |
4 |
Correct |
13 ms |
10708 KB |
Output is correct |
5 |
Correct |
14 ms |
10676 KB |
Output is correct |
6 |
Correct |
18 ms |
10672 KB |
Output is correct |
7 |
Correct |
17 ms |
10724 KB |
Output is correct |
8 |
Correct |
17 ms |
10696 KB |
Output is correct |
9 |
Correct |
20 ms |
10672 KB |
Output is correct |
10 |
Correct |
18 ms |
10676 KB |
Output is correct |
11 |
Correct |
13 ms |
10776 KB |
Output is correct |
12 |
Correct |
12 ms |
10708 KB |
Output is correct |
13 |
Correct |
14 ms |
10772 KB |
Output is correct |
14 |
Correct |
14 ms |
10736 KB |
Output is correct |
15 |
Correct |
17 ms |
10688 KB |
Output is correct |
16 |
Correct |
9 ms |
9720 KB |
Output is correct |
17 |
Correct |
9 ms |
9684 KB |
Output is correct |
18 |
Correct |
8 ms |
9628 KB |
Output is correct |
19 |
Correct |
7 ms |
9684 KB |
Output is correct |
20 |
Correct |
7 ms |
9684 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
18352 KB |
Output is correct |
2 |
Correct |
13 ms |
18324 KB |
Output is correct |
3 |
Correct |
13 ms |
18436 KB |
Output is correct |
4 |
Correct |
14 ms |
18360 KB |
Output is correct |
5 |
Correct |
16 ms |
18364 KB |
Output is correct |
6 |
Correct |
15 ms |
18436 KB |
Output is correct |
7 |
Correct |
15 ms |
18356 KB |
Output is correct |
8 |
Correct |
13 ms |
18388 KB |
Output is correct |
9 |
Correct |
13 ms |
18364 KB |
Output is correct |
10 |
Correct |
13 ms |
18380 KB |
Output is correct |
11 |
Correct |
13 ms |
18428 KB |
Output is correct |
12 |
Correct |
13 ms |
18332 KB |
Output is correct |
13 |
Correct |
13 ms |
18388 KB |
Output is correct |
14 |
Correct |
12 ms |
18384 KB |
Output is correct |
15 |
Correct |
13 ms |
18388 KB |
Output is correct |
16 |
Correct |
7 ms |
11860 KB |
Output is correct |
17 |
Correct |
8 ms |
11988 KB |
Output is correct |
18 |
Correct |
8 ms |
11860 KB |
Output is correct |
19 |
Correct |
9 ms |
11988 KB |
Output is correct |
20 |
Correct |
7 ms |
11932 KB |
Output is correct |
21 |
Correct |
833 ms |
23176 KB |
Output is correct |
22 |
Correct |
824 ms |
23200 KB |
Output is correct |
23 |
Correct |
755 ms |
23116 KB |
Output is correct |
24 |
Correct |
811 ms |
23240 KB |
Output is correct |
25 |
Correct |
877 ms |
23052 KB |
Output is correct |
26 |
Correct |
1484 ms |
22816 KB |
Output is correct |
27 |
Correct |
1412 ms |
22732 KB |
Output is correct |
28 |
Correct |
1445 ms |
22704 KB |
Output is correct |
29 |
Correct |
1482 ms |
23004 KB |
Output is correct |
30 |
Correct |
28 ms |
23840 KB |
Output is correct |
31 |
Correct |
24 ms |
23804 KB |
Output is correct |
32 |
Correct |
21 ms |
23892 KB |
Output is correct |
33 |
Correct |
25 ms |
23824 KB |
Output is correct |
34 |
Correct |
21 ms |
23796 KB |
Output is correct |
35 |
Correct |
15 ms |
18388 KB |
Output is correct |
36 |
Correct |
15 ms |
18368 KB |
Output is correct |
37 |
Correct |
16 ms |
18388 KB |
Output is correct |
38 |
Correct |
17 ms |
18432 KB |
Output is correct |
39 |
Correct |
14 ms |
10724 KB |
Output is correct |
40 |
Correct |
12 ms |
10688 KB |
Output is correct |
41 |
Correct |
13 ms |
10708 KB |
Output is correct |
42 |
Correct |
13 ms |
10708 KB |
Output is correct |
43 |
Correct |
14 ms |
10676 KB |
Output is correct |
44 |
Correct |
18 ms |
10672 KB |
Output is correct |
45 |
Correct |
17 ms |
10724 KB |
Output is correct |
46 |
Correct |
17 ms |
10696 KB |
Output is correct |
47 |
Correct |
20 ms |
10672 KB |
Output is correct |
48 |
Correct |
18 ms |
10676 KB |
Output is correct |
49 |
Correct |
13 ms |
10776 KB |
Output is correct |
50 |
Correct |
12 ms |
10708 KB |
Output is correct |
51 |
Correct |
14 ms |
10772 KB |
Output is correct |
52 |
Correct |
14 ms |
10736 KB |
Output is correct |
53 |
Correct |
17 ms |
10688 KB |
Output is correct |
54 |
Correct |
9 ms |
9720 KB |
Output is correct |
55 |
Correct |
9 ms |
9684 KB |
Output is correct |
56 |
Correct |
8 ms |
9628 KB |
Output is correct |
57 |
Correct |
7 ms |
9684 KB |
Output is correct |
58 |
Correct |
7 ms |
9684 KB |
Output is correct |
59 |
Correct |
1027 ms |
24500 KB |
Output is correct |
60 |
Correct |
918 ms |
24500 KB |
Output is correct |
61 |
Correct |
892 ms |
24408 KB |
Output is correct |
62 |
Correct |
991 ms |
24516 KB |
Output is correct |
63 |
Correct |
979 ms |
24688 KB |
Output is correct |
64 |
Correct |
1859 ms |
24492 KB |
Output is correct |
65 |
Correct |
1848 ms |
24556 KB |
Output is correct |
66 |
Correct |
1820 ms |
24420 KB |
Output is correct |
67 |
Correct |
1789 ms |
24396 KB |
Output is correct |
68 |
Correct |
1875 ms |
24504 KB |
Output is correct |
69 |
Correct |
1041 ms |
24484 KB |
Output is correct |
70 |
Correct |
990 ms |
24412 KB |
Output is correct |
71 |
Correct |
1012 ms |
24488 KB |
Output is correct |
72 |
Correct |
1102 ms |
24496 KB |
Output is correct |
73 |
Correct |
1063 ms |
24464 KB |
Output is correct |
74 |
Correct |
106 ms |
12036 KB |
Output is correct |
75 |
Correct |
105 ms |
12076 KB |
Output is correct |
76 |
Correct |
111 ms |
12236 KB |
Output is correct |
77 |
Correct |
111 ms |
12072 KB |
Output is correct |
78 |
Correct |
127 ms |
12076 KB |
Output is correct |