#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define SZ(x) (int) x.size()
const int mod = 1e9 + 7;
struct mint {
int v;
mint(long long x) {
if (x >= mod) x %= mod;
v = x;
}
mint() {v = 0;}
mint& operator+=(mint b) {
if ((v += b.v) >= mod) {
v -= mod;
}
return *this;
}
mint& operator-=(mint b) {
if ((v -= b.v) < 0) {
v += mod;
}
return *this;
}
mint& operator*=(mint b) {
v = 1ll * v * b.v % mod;
return *this;
}
mint power(mint a, int b) {
mint ans = 1;
while (b) {
if (b & 1) {
ans *= a;
}
a *= a, b >>= 1;
}
return ans;
}
mint& operator/=(mint b) {
v = 1ll * v * power(b, mod - 2).v % mod;
return *this;
}
friend mint operator+(mint a, mint b) {
return a += b;
}
friend mint operator-(mint a, mint b) {
return a -= b;
}
friend mint operator*(mint a, mint b) {
return a *= b;
}
friend mint operator/(mint a, mint b) {
return a /= b;
}
friend istream& operator>>(istream &is, mint &a) {
return is >> a.v;
}
friend ostream& operator<<(ostream &os, mint a) {
return os << a.v;
}
};
const int N = 505;
mint inv[N];
int main() {
ios_base::sync_with_stdio(0), cin.tie(0);
for (int i = 1; i < N; i++) {
inv[i] = mint(1) / i;
}
int n;
cin >> n;
array<int, 2> a[n];
vector<int> v;
for (int i = 0; i < n; i++) {
cin >> a[i][0] >> a[i][1];
v.push_back(a[i][0]);
v.push_back(a[i][1]);
v.push_back(a[i][1] + 1);
}
sort(v.begin(), v.end());
v.resize(unique(v.begin(), v.end()) - v.begin());
auto get = [&] (int x) {
return lower_bound(v.begin(), v.end(), x) - v.begin();
};
int m = v.size();
vector<int> gud[m];
for (int i = 0; i < n; i++) {
int l = get(a[i][0]), r = get(a[i][1]);
for (int j = l; j <= r; j++) {
gud[j].push_back(i + 1);
}
}
mint dp[m + 1][n + 1];
for (int j = 1; j <= n; j++) {
dp[m][j] = 1;
}
for (int i = m - 1; i >= 0; i--) {
int sz = gud[i].size();
mint dp2[sz + 1][sz + 1];
for (int j = sz - 1; j >= 0; j--) {
for (int k = 1; k <= sz; k++) {
dp2[j][k] += dp2[j + 1][k];
if (k == 1) {
dp2[j][k] += dp[i + 1][gud[i][j]];
} else {
dp2[j][k] += dp2[j + 1][k - 1];
}
}
}
for (int j = 0; j <= n; j++) {
int pos = SZ(gud[i]);
for (int k = 0; k < SZ(gud[i]); k++) {
if (j < gud[i][k]) {
pos = k;
break;
}
}
dp[i][j] = dp[i + 1][j];
int slots = v[i + 1] - v[i];
mint C = 1;
for (int k = 1; k <= min(SZ(gud[i]) - pos, slots); k++) {
C *= (slots - k + 1) * inv[k];
dp[i][j] += dp2[pos][k] * C;
}
}
}
// for (int i = 0; i < m; i++) {
// for (int j = 0; j <= n; j++) {
// cout << dp[i][j] << ' ';
// }
// cout << '\n';
// }
cout << dp[0][0] << '\n';
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
2392 KB |
Output is correct |
2 |
Correct |
3 ms |
2392 KB |
Output is correct |
3 |
Correct |
4 ms |
2396 KB |
Output is correct |
4 |
Correct |
3 ms |
2384 KB |
Output is correct |
5 |
Correct |
3 ms |
2396 KB |
Output is correct |
6 |
Correct |
3 ms |
2396 KB |
Output is correct |
7 |
Correct |
3 ms |
2396 KB |
Output is correct |
8 |
Correct |
3 ms |
2396 KB |
Output is correct |
9 |
Correct |
3 ms |
2396 KB |
Output is correct |
10 |
Correct |
3 ms |
2396 KB |
Output is correct |
11 |
Correct |
3 ms |
2392 KB |
Output is correct |
12 |
Correct |
3 ms |
2392 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 |
2396 KB |
Output is correct |
16 |
Correct |
1 ms |
604 KB |
Output is correct |
17 |
Correct |
2 ms |
788 KB |
Output is correct |
18 |
Correct |
1 ms |
604 KB |
Output is correct |
19 |
Correct |
1 ms |
604 KB |
Output is correct |
20 |
Correct |
1 ms |
604 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
2392 KB |
Output is correct |
2 |
Correct |
3 ms |
2392 KB |
Output is correct |
3 |
Correct |
4 ms |
2396 KB |
Output is correct |
4 |
Correct |
3 ms |
2384 KB |
Output is correct |
5 |
Correct |
3 ms |
2396 KB |
Output is correct |
6 |
Correct |
3 ms |
2396 KB |
Output is correct |
7 |
Correct |
3 ms |
2396 KB |
Output is correct |
8 |
Correct |
3 ms |
2396 KB |
Output is correct |
9 |
Correct |
3 ms |
2396 KB |
Output is correct |
10 |
Correct |
3 ms |
2396 KB |
Output is correct |
11 |
Correct |
3 ms |
2392 KB |
Output is correct |
12 |
Correct |
3 ms |
2392 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 |
2396 KB |
Output is correct |
16 |
Correct |
1 ms |
604 KB |
Output is correct |
17 |
Correct |
2 ms |
788 KB |
Output is correct |
18 |
Correct |
1 ms |
604 KB |
Output is correct |
19 |
Correct |
1 ms |
604 KB |
Output is correct |
20 |
Correct |
1 ms |
604 KB |
Output is correct |
21 |
Correct |
122 ms |
4620 KB |
Output is correct |
22 |
Correct |
118 ms |
4688 KB |
Output is correct |
23 |
Correct |
106 ms |
4360 KB |
Output is correct |
24 |
Correct |
117 ms |
4444 KB |
Output is correct |
25 |
Correct |
129 ms |
4436 KB |
Output is correct |
26 |
Correct |
209 ms |
5480 KB |
Output is correct |
27 |
Correct |
218 ms |
5724 KB |
Output is correct |
28 |
Correct |
228 ms |
5464 KB |
Output is correct |
29 |
Correct |
210 ms |
5364 KB |
Output is correct |
30 |
Correct |
7 ms |
3160 KB |
Output is correct |
31 |
Correct |
7 ms |
3164 KB |
Output is correct |
32 |
Correct |
7 ms |
3164 KB |
Output is correct |
33 |
Correct |
6 ms |
3408 KB |
Output is correct |
34 |
Correct |
7 ms |
3164 KB |
Output is correct |
35 |
Correct |
5 ms |
2392 KB |
Output is correct |
36 |
Correct |
5 ms |
2396 KB |
Output is correct |
37 |
Correct |
4 ms |
2396 KB |
Output is correct |
38 |
Correct |
5 ms |
2392 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
604 KB |
Output is correct |
2 |
Correct |
3 ms |
668 KB |
Output is correct |
3 |
Correct |
3 ms |
604 KB |
Output is correct |
4 |
Correct |
5 ms |
692 KB |
Output is correct |
5 |
Correct |
5 ms |
600 KB |
Output is correct |
6 |
Correct |
7 ms |
604 KB |
Output is correct |
7 |
Correct |
6 ms |
604 KB |
Output is correct |
8 |
Correct |
6 ms |
856 KB |
Output is correct |
9 |
Correct |
6 ms |
708 KB |
Output is correct |
10 |
Correct |
6 ms |
604 KB |
Output is correct |
11 |
Correct |
4 ms |
688 KB |
Output is correct |
12 |
Correct |
4 ms |
604 KB |
Output is correct |
13 |
Correct |
3 ms |
456 KB |
Output is correct |
14 |
Correct |
3 ms |
604 KB |
Output is correct |
15 |
Correct |
4 ms |
680 KB |
Output is correct |
16 |
Correct |
2 ms |
348 KB |
Output is correct |
17 |
Correct |
3 ms |
344 KB |
Output is correct |
18 |
Correct |
3 ms |
348 KB |
Output is correct |
19 |
Correct |
2 ms |
348 KB |
Output is correct |
20 |
Correct |
2 ms |
580 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
2392 KB |
Output is correct |
2 |
Correct |
3 ms |
2392 KB |
Output is correct |
3 |
Correct |
4 ms |
2396 KB |
Output is correct |
4 |
Correct |
3 ms |
2384 KB |
Output is correct |
5 |
Correct |
3 ms |
2396 KB |
Output is correct |
6 |
Correct |
3 ms |
2396 KB |
Output is correct |
7 |
Correct |
3 ms |
2396 KB |
Output is correct |
8 |
Correct |
3 ms |
2396 KB |
Output is correct |
9 |
Correct |
3 ms |
2396 KB |
Output is correct |
10 |
Correct |
3 ms |
2396 KB |
Output is correct |
11 |
Correct |
3 ms |
2392 KB |
Output is correct |
12 |
Correct |
3 ms |
2392 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 |
2396 KB |
Output is correct |
16 |
Correct |
1 ms |
604 KB |
Output is correct |
17 |
Correct |
2 ms |
788 KB |
Output is correct |
18 |
Correct |
1 ms |
604 KB |
Output is correct |
19 |
Correct |
1 ms |
604 KB |
Output is correct |
20 |
Correct |
1 ms |
604 KB |
Output is correct |
21 |
Correct |
122 ms |
4620 KB |
Output is correct |
22 |
Correct |
118 ms |
4688 KB |
Output is correct |
23 |
Correct |
106 ms |
4360 KB |
Output is correct |
24 |
Correct |
117 ms |
4444 KB |
Output is correct |
25 |
Correct |
129 ms |
4436 KB |
Output is correct |
26 |
Correct |
209 ms |
5480 KB |
Output is correct |
27 |
Correct |
218 ms |
5724 KB |
Output is correct |
28 |
Correct |
228 ms |
5464 KB |
Output is correct |
29 |
Correct |
210 ms |
5364 KB |
Output is correct |
30 |
Correct |
7 ms |
3160 KB |
Output is correct |
31 |
Correct |
7 ms |
3164 KB |
Output is correct |
32 |
Correct |
7 ms |
3164 KB |
Output is correct |
33 |
Correct |
6 ms |
3408 KB |
Output is correct |
34 |
Correct |
7 ms |
3164 KB |
Output is correct |
35 |
Correct |
5 ms |
2392 KB |
Output is correct |
36 |
Correct |
5 ms |
2396 KB |
Output is correct |
37 |
Correct |
4 ms |
2396 KB |
Output is correct |
38 |
Correct |
5 ms |
2392 KB |
Output is correct |
39 |
Correct |
4 ms |
604 KB |
Output is correct |
40 |
Correct |
3 ms |
668 KB |
Output is correct |
41 |
Correct |
3 ms |
604 KB |
Output is correct |
42 |
Correct |
5 ms |
692 KB |
Output is correct |
43 |
Correct |
5 ms |
600 KB |
Output is correct |
44 |
Correct |
7 ms |
604 KB |
Output is correct |
45 |
Correct |
6 ms |
604 KB |
Output is correct |
46 |
Correct |
6 ms |
856 KB |
Output is correct |
47 |
Correct |
6 ms |
708 KB |
Output is correct |
48 |
Correct |
6 ms |
604 KB |
Output is correct |
49 |
Correct |
4 ms |
688 KB |
Output is correct |
50 |
Correct |
4 ms |
604 KB |
Output is correct |
51 |
Correct |
3 ms |
456 KB |
Output is correct |
52 |
Correct |
3 ms |
604 KB |
Output is correct |
53 |
Correct |
4 ms |
680 KB |
Output is correct |
54 |
Correct |
2 ms |
348 KB |
Output is correct |
55 |
Correct |
3 ms |
344 KB |
Output is correct |
56 |
Correct |
3 ms |
348 KB |
Output is correct |
57 |
Correct |
2 ms |
348 KB |
Output is correct |
58 |
Correct |
2 ms |
580 KB |
Output is correct |
59 |
Correct |
374 ms |
5156 KB |
Output is correct |
60 |
Correct |
355 ms |
5212 KB |
Output is correct |
61 |
Correct |
337 ms |
5044 KB |
Output is correct |
62 |
Correct |
379 ms |
5636 KB |
Output is correct |
63 |
Correct |
364 ms |
4944 KB |
Output is correct |
64 |
Correct |
635 ms |
6460 KB |
Output is correct |
65 |
Correct |
617 ms |
6456 KB |
Output is correct |
66 |
Correct |
609 ms |
6224 KB |
Output is correct |
67 |
Correct |
616 ms |
6228 KB |
Output is correct |
68 |
Correct |
640 ms |
6548 KB |
Output is correct |
69 |
Correct |
302 ms |
4948 KB |
Output is correct |
70 |
Correct |
305 ms |
4816 KB |
Output is correct |
71 |
Correct |
299 ms |
4960 KB |
Output is correct |
72 |
Correct |
314 ms |
5228 KB |
Output is correct |
73 |
Correct |
324 ms |
5052 KB |
Output is correct |
74 |
Correct |
43 ms |
1116 KB |
Output is correct |
75 |
Correct |
43 ms |
1296 KB |
Output is correct |
76 |
Correct |
42 ms |
1288 KB |
Output is correct |
77 |
Correct |
42 ms |
1116 KB |
Output is correct |
78 |
Correct |
43 ms |
1332 KB |
Output is correct |