#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define all(x) (x).begin(),(x).end()
#define X first
#define Y second
#define sep ' '
#define endl '\n'
#define debug(x) cerr << #x << ": " << x << endl;
const ll MAXN = 1000 + 10;
const ll MOD = 1e9 + 7;
void mkey(int& a) {
if (a >= MOD) a -= MOD;
}
inline ll poww(ll a, ll b) {
ll ans = 1;
while (b) {
if (b & 1) ans = ans * a % MOD;
b >>= 1;
a = a * a % MOD;
}
return ans;
}
int n, L[MAXN], R[MAXN], C[MAXN][MAXN], PC[MAXN][MAXN], dp[MAXN][MAXN],
ps[MAXN][MAXN], inv[MAXN];
vector<int> vec;
inline int ind(int x) {
return lower_bound(all(vec), x) - vec.begin();
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
C[0][0] = 1;
for (int i = 1; i < MAXN; i++) {
C[i][0] = 1;
for (int j = 1; j <= i; j++)
mkey(C[i][j] = C[i - 1][j - 1] + C[i - 1][j]);
}
cin >> n;
for (int i = 1; i <= n; i++) {
cin >> L[i] >> R[i];
vec.push_back(L[i] - 1);
vec.push_back(R[i]);
inv[i] = poww(i, MOD - 2);
}
vec.push_back(-1);
sort(all(vec));
vec.resize(unique(all(vec)) - vec.begin());
for (int j = 1; j < int(vec.size()); j++) {
for (int i = 1; i <= n; i++) {
ps[j][i] = ps[j][i - 1] + (vec[j - 1] + 1 >= L[i] && vec[j] <= R[i]);
}
int sz = vec[j] - vec[j - 1];
for (int k = 1; k <= n; k++) {
ll f = 1;
for (int i = 1; i <= min(sz, k); i++) {
f = f * (sz - i + 1) % MOD * inv[i] % MOD;
mkey(PC[j][k] += f * C[k - 1][i - 1] % MOD);
}
}
}
fill(dp[0], dp[0] + MAXN, 1);
int ans = 0;
for (int i = 1; i <= n; i++) {
int l = ind(L[i] - 1), r = ind(R[i]);
for (int j = 1; j < int(vec.size()); j++) {
dp[i][j] = dp[i][j - 1];
if (j > l && j <= r) {
for (int k = 0; k < i; k++) {
dp[i][j] = (dp[i][j] + 1ll * PC[j][ps[j][i] - ps[j][k]] * dp[k][j - 1]) % MOD;
}
}
}
mkey(ans += dp[i][int(vec.size()) - 1]);
}
cout << ans << endl;
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
665 ms |
14244 KB |
Output is correct |
2 |
Correct |
677 ms |
14112 KB |
Output is correct |
3 |
Correct |
673 ms |
14284 KB |
Output is correct |
4 |
Correct |
707 ms |
14264 KB |
Output is correct |
5 |
Correct |
674 ms |
14196 KB |
Output is correct |
6 |
Correct |
669 ms |
14252 KB |
Output is correct |
7 |
Correct |
666 ms |
14212 KB |
Output is correct |
8 |
Correct |
675 ms |
14220 KB |
Output is correct |
9 |
Correct |
683 ms |
14260 KB |
Output is correct |
10 |
Correct |
667 ms |
14380 KB |
Output is correct |
11 |
Correct |
673 ms |
14316 KB |
Output is correct |
12 |
Correct |
678 ms |
14292 KB |
Output is correct |
13 |
Correct |
665 ms |
14320 KB |
Output is correct |
14 |
Correct |
677 ms |
14284 KB |
Output is correct |
15 |
Correct |
688 ms |
14160 KB |
Output is correct |
16 |
Correct |
123 ms |
7724 KB |
Output is correct |
17 |
Correct |
135 ms |
7816 KB |
Output is correct |
18 |
Correct |
129 ms |
7760 KB |
Output is correct |
19 |
Correct |
133 ms |
7828 KB |
Output is correct |
20 |
Correct |
130 ms |
7756 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
665 ms |
14244 KB |
Output is correct |
2 |
Correct |
677 ms |
14112 KB |
Output is correct |
3 |
Correct |
673 ms |
14284 KB |
Output is correct |
4 |
Correct |
707 ms |
14264 KB |
Output is correct |
5 |
Correct |
674 ms |
14196 KB |
Output is correct |
6 |
Correct |
669 ms |
14252 KB |
Output is correct |
7 |
Correct |
666 ms |
14212 KB |
Output is correct |
8 |
Correct |
675 ms |
14220 KB |
Output is correct |
9 |
Correct |
683 ms |
14260 KB |
Output is correct |
10 |
Correct |
667 ms |
14380 KB |
Output is correct |
11 |
Correct |
673 ms |
14316 KB |
Output is correct |
12 |
Correct |
678 ms |
14292 KB |
Output is correct |
13 |
Correct |
665 ms |
14320 KB |
Output is correct |
14 |
Correct |
677 ms |
14284 KB |
Output is correct |
15 |
Correct |
688 ms |
14160 KB |
Output is correct |
16 |
Correct |
123 ms |
7724 KB |
Output is correct |
17 |
Correct |
135 ms |
7816 KB |
Output is correct |
18 |
Correct |
129 ms |
7760 KB |
Output is correct |
19 |
Correct |
133 ms |
7828 KB |
Output is correct |
20 |
Correct |
130 ms |
7756 KB |
Output is correct |
21 |
Correct |
226 ms |
13632 KB |
Output is correct |
22 |
Correct |
233 ms |
13516 KB |
Output is correct |
23 |
Correct |
208 ms |
13516 KB |
Output is correct |
24 |
Correct |
216 ms |
13428 KB |
Output is correct |
25 |
Correct |
215 ms |
13448 KB |
Output is correct |
26 |
Correct |
289 ms |
13196 KB |
Output is correct |
27 |
Correct |
292 ms |
13324 KB |
Output is correct |
28 |
Correct |
279 ms |
13240 KB |
Output is correct |
29 |
Correct |
282 ms |
13260 KB |
Output is correct |
30 |
Correct |
639 ms |
14140 KB |
Output is correct |
31 |
Correct |
656 ms |
14188 KB |
Output is correct |
32 |
Correct |
649 ms |
14200 KB |
Output is correct |
33 |
Correct |
693 ms |
14172 KB |
Output is correct |
34 |
Correct |
676 ms |
14196 KB |
Output is correct |
35 |
Correct |
669 ms |
14128 KB |
Output is correct |
36 |
Correct |
665 ms |
14104 KB |
Output is correct |
37 |
Correct |
700 ms |
14284 KB |
Output is correct |
38 |
Correct |
670 ms |
14168 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
19 ms |
6228 KB |
Output is correct |
2 |
Correct |
18 ms |
6260 KB |
Output is correct |
3 |
Correct |
18 ms |
6324 KB |
Output is correct |
4 |
Correct |
20 ms |
6220 KB |
Output is correct |
5 |
Correct |
19 ms |
6316 KB |
Output is correct |
6 |
Correct |
20 ms |
6256 KB |
Output is correct |
7 |
Correct |
18 ms |
6228 KB |
Output is correct |
8 |
Correct |
20 ms |
6228 KB |
Output is correct |
9 |
Correct |
20 ms |
6288 KB |
Output is correct |
10 |
Correct |
18 ms |
6308 KB |
Output is correct |
11 |
Correct |
18 ms |
6252 KB |
Output is correct |
12 |
Correct |
19 ms |
6268 KB |
Output is correct |
13 |
Correct |
17 ms |
6312 KB |
Output is correct |
14 |
Correct |
16 ms |
6228 KB |
Output is correct |
15 |
Correct |
17 ms |
6228 KB |
Output is correct |
16 |
Correct |
13 ms |
5568 KB |
Output is correct |
17 |
Correct |
11 ms |
5588 KB |
Output is correct |
18 |
Correct |
12 ms |
5568 KB |
Output is correct |
19 |
Correct |
12 ms |
5588 KB |
Output is correct |
20 |
Correct |
11 ms |
5528 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
665 ms |
14244 KB |
Output is correct |
2 |
Correct |
677 ms |
14112 KB |
Output is correct |
3 |
Correct |
673 ms |
14284 KB |
Output is correct |
4 |
Correct |
707 ms |
14264 KB |
Output is correct |
5 |
Correct |
674 ms |
14196 KB |
Output is correct |
6 |
Correct |
669 ms |
14252 KB |
Output is correct |
7 |
Correct |
666 ms |
14212 KB |
Output is correct |
8 |
Correct |
675 ms |
14220 KB |
Output is correct |
9 |
Correct |
683 ms |
14260 KB |
Output is correct |
10 |
Correct |
667 ms |
14380 KB |
Output is correct |
11 |
Correct |
673 ms |
14316 KB |
Output is correct |
12 |
Correct |
678 ms |
14292 KB |
Output is correct |
13 |
Correct |
665 ms |
14320 KB |
Output is correct |
14 |
Correct |
677 ms |
14284 KB |
Output is correct |
15 |
Correct |
688 ms |
14160 KB |
Output is correct |
16 |
Correct |
123 ms |
7724 KB |
Output is correct |
17 |
Correct |
135 ms |
7816 KB |
Output is correct |
18 |
Correct |
129 ms |
7760 KB |
Output is correct |
19 |
Correct |
133 ms |
7828 KB |
Output is correct |
20 |
Correct |
130 ms |
7756 KB |
Output is correct |
21 |
Correct |
226 ms |
13632 KB |
Output is correct |
22 |
Correct |
233 ms |
13516 KB |
Output is correct |
23 |
Correct |
208 ms |
13516 KB |
Output is correct |
24 |
Correct |
216 ms |
13428 KB |
Output is correct |
25 |
Correct |
215 ms |
13448 KB |
Output is correct |
26 |
Correct |
289 ms |
13196 KB |
Output is correct |
27 |
Correct |
292 ms |
13324 KB |
Output is correct |
28 |
Correct |
279 ms |
13240 KB |
Output is correct |
29 |
Correct |
282 ms |
13260 KB |
Output is correct |
30 |
Correct |
639 ms |
14140 KB |
Output is correct |
31 |
Correct |
656 ms |
14188 KB |
Output is correct |
32 |
Correct |
649 ms |
14200 KB |
Output is correct |
33 |
Correct |
693 ms |
14172 KB |
Output is correct |
34 |
Correct |
676 ms |
14196 KB |
Output is correct |
35 |
Correct |
669 ms |
14128 KB |
Output is correct |
36 |
Correct |
665 ms |
14104 KB |
Output is correct |
37 |
Correct |
700 ms |
14284 KB |
Output is correct |
38 |
Correct |
670 ms |
14168 KB |
Output is correct |
39 |
Correct |
19 ms |
6228 KB |
Output is correct |
40 |
Correct |
18 ms |
6260 KB |
Output is correct |
41 |
Correct |
18 ms |
6324 KB |
Output is correct |
42 |
Correct |
20 ms |
6220 KB |
Output is correct |
43 |
Correct |
19 ms |
6316 KB |
Output is correct |
44 |
Correct |
20 ms |
6256 KB |
Output is correct |
45 |
Correct |
18 ms |
6228 KB |
Output is correct |
46 |
Correct |
20 ms |
6228 KB |
Output is correct |
47 |
Correct |
20 ms |
6288 KB |
Output is correct |
48 |
Correct |
18 ms |
6308 KB |
Output is correct |
49 |
Correct |
18 ms |
6252 KB |
Output is correct |
50 |
Correct |
19 ms |
6268 KB |
Output is correct |
51 |
Correct |
17 ms |
6312 KB |
Output is correct |
52 |
Correct |
16 ms |
6228 KB |
Output is correct |
53 |
Correct |
17 ms |
6228 KB |
Output is correct |
54 |
Correct |
13 ms |
5568 KB |
Output is correct |
55 |
Correct |
11 ms |
5588 KB |
Output is correct |
56 |
Correct |
12 ms |
5568 KB |
Output is correct |
57 |
Correct |
12 ms |
5588 KB |
Output is correct |
58 |
Correct |
11 ms |
5528 KB |
Output is correct |
59 |
Correct |
1563 ms |
14176 KB |
Output is correct |
60 |
Correct |
1507 ms |
14192 KB |
Output is correct |
61 |
Correct |
1501 ms |
14288 KB |
Output is correct |
62 |
Correct |
1524 ms |
14164 KB |
Output is correct |
63 |
Correct |
1508 ms |
14164 KB |
Output is correct |
64 |
Correct |
1624 ms |
14196 KB |
Output is correct |
65 |
Correct |
1652 ms |
14148 KB |
Output is correct |
66 |
Correct |
1605 ms |
14216 KB |
Output is correct |
67 |
Correct |
1610 ms |
14224 KB |
Output is correct |
68 |
Correct |
1610 ms |
14308 KB |
Output is correct |
69 |
Correct |
1470 ms |
14156 KB |
Output is correct |
70 |
Correct |
1453 ms |
14196 KB |
Output is correct |
71 |
Correct |
1474 ms |
14204 KB |
Output is correct |
72 |
Correct |
1463 ms |
14304 KB |
Output is correct |
73 |
Correct |
1467 ms |
14300 KB |
Output is correct |
74 |
Correct |
181 ms |
7660 KB |
Output is correct |
75 |
Correct |
172 ms |
7748 KB |
Output is correct |
76 |
Correct |
180 ms |
7776 KB |
Output is correct |
77 |
Correct |
178 ms |
7876 KB |
Output is correct |
78 |
Correct |
182 ms |
7640 KB |
Output is correct |