#include <bits/stdc++.h>
#define ll long long
#define rep(i,m,n) for(int i=(m); i<=(n); i++)
#define reb(i,m,n) for(int i=(m); i>=(n); i--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define MP make_pair
#define fs first
#define se second
#define bit(msk, i) ((msk >> i) & 1)
#define iter(id, v) for(auto id : v)
#define pb push_back
#define SZ(v) (ll)v.size()
#define ALL(v) v.begin(),v.end()
using namespace std;
mt19937_64 rd(chrono :: steady_clock :: now ().time_since_epoch().count());
ll Rand (ll l, ll r) { return uniform_int_distribution<ll> (l, r) (rd); }
const int N = 5e2 + 7;
const int Mod = 1e9 + 7;
const int INF = 1e9;
const ll BASE = 137;
const int szBL = 320;
int n, m;
pii a[N];
int dp[N][N * 2], f[N][N * 2], com[N * 2][N], combi[N][N];
inline void add (int &a, int b) { a = a + b; if (a >= Mod) a = a - Mod; }
ll power (int n, int m) {
if (m == 0) return 1;
ll t = power (n, m >> 1);
(t *= t) %= Mod;
if (m & 1) (t *= n) %= Mod;
return t;
}
bool cover (pii A, pii B) {
return A.fs <= B.fs && A.se >= B.se;
}
void solution () {
cin >> n;
vector<pii> vec, seg = {MP(0, 0)};
rep (i, 1, n) {
cin >> a[i].fs >> a[i].se;
vec.pb({a[i].fs, 0}), vec.pb({a[i].se, 1});
}
sort (ALL(vec));
vec.resize(unique(ALL(vec)) - vec.begin());
rep (i, 0, SZ(vec) - 2) {
if (vec[i].se == vec[i + 1].se) {
if (vec[i].se == 1) seg.pb({vec[i].fs + 1, vec[i + 1].fs});
else seg.pb({vec[i].fs, vec[i + 1].fs - 1});
}
else {
if (vec[i].se == 0) seg.pb({vec[i].fs, vec[i + 1].fs});
else seg.pb({vec[i].fs + 1, vec[i +1 ].fs - 1});
}
}
m = SZ(seg) - 1;
rep (i, 0, m) {
int Len = seg[i].se - seg[i].fs + 1;
com[i][0] = 1;
rep (j, 1, n + 1) {
if (j > Len) com[i][j] = 0;
else com[i][j] = 1LL * com[i][j - 1] * (Len - j + 1) % Mod * power (j, Mod - 2) % Mod;
}
// cout << seg[i].fs <<","<<seg[i].se<<"\n";
}
rep (i, 0, n) {
rep (j, 0, i) {
if (j == i || j == 0) combi[i][j] = 1;
else combi[i][j] = (combi[i - 1][j - 1] + combi[i - 1][j]) % Mod;
}
}
rep (i, 0, n) {
rep (j, 0, m) {
rep (k, 0, i) {
add(f[i][j], 1LL * combi[i][k] * com[j][k + 1] % Mod);
}
}
}
rep (j, 0, m) dp[0][j] = 1;
rep (i, 1, n) {
dp[i][0] = 1;
rep (j, 1, m) {
dp[i][j] = dp[i][j - 1];
int num = 0;
reb (k, i, 1) {
if (cover(a[k], seg[j])) {
add(dp[i][j], 1LL * dp[k - 1][j - 1] * f[num][j] % Mod);
++num;
}
}
// cout << i <<" "<<seg[j].fs<<","<<seg[j].se<<": "<<dp[i][j] <<"\n";
}
}
cout << (dp[n][m] - 1 + Mod) % Mod <<"\n";
}
#define file(name) freopen(name".inp","r",stdin); \
freopen(name".out","w",stdout);
int main () {
// file("c");
ios_base :: sync_with_stdio(false); cin.tie(0); cout.tie(0);
int num_Test = 1;
// cin >> num_Test;
while (num_Test--)
solution();
}
/*
no bug challenge +4
mình có muốn dùng mảng này không?
4 5
1 3
4 1
1 2
3 2
2 1
return->break
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
402 ms |
7252 KB |
Output is correct |
2 |
Correct |
417 ms |
7252 KB |
Output is correct |
3 |
Correct |
408 ms |
7248 KB |
Output is correct |
4 |
Correct |
425 ms |
7504 KB |
Output is correct |
5 |
Correct |
431 ms |
7252 KB |
Output is correct |
6 |
Correct |
396 ms |
7504 KB |
Output is correct |
7 |
Correct |
389 ms |
7344 KB |
Output is correct |
8 |
Correct |
401 ms |
7328 KB |
Output is correct |
9 |
Correct |
403 ms |
7504 KB |
Output is correct |
10 |
Correct |
389 ms |
7248 KB |
Output is correct |
11 |
Correct |
403 ms |
7268 KB |
Output is correct |
12 |
Correct |
401 ms |
7248 KB |
Output is correct |
13 |
Correct |
395 ms |
7252 KB |
Output is correct |
14 |
Correct |
385 ms |
7416 KB |
Output is correct |
15 |
Correct |
398 ms |
7380 KB |
Output is correct |
16 |
Correct |
75 ms |
5716 KB |
Output is correct |
17 |
Correct |
83 ms |
5712 KB |
Output is correct |
18 |
Correct |
80 ms |
5772 KB |
Output is correct |
19 |
Correct |
81 ms |
6104 KB |
Output is correct |
20 |
Correct |
80 ms |
5712 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
402 ms |
7252 KB |
Output is correct |
2 |
Correct |
417 ms |
7252 KB |
Output is correct |
3 |
Correct |
408 ms |
7248 KB |
Output is correct |
4 |
Correct |
425 ms |
7504 KB |
Output is correct |
5 |
Correct |
431 ms |
7252 KB |
Output is correct |
6 |
Correct |
396 ms |
7504 KB |
Output is correct |
7 |
Correct |
389 ms |
7344 KB |
Output is correct |
8 |
Correct |
401 ms |
7328 KB |
Output is correct |
9 |
Correct |
403 ms |
7504 KB |
Output is correct |
10 |
Correct |
389 ms |
7248 KB |
Output is correct |
11 |
Correct |
403 ms |
7268 KB |
Output is correct |
12 |
Correct |
401 ms |
7248 KB |
Output is correct |
13 |
Correct |
395 ms |
7252 KB |
Output is correct |
14 |
Correct |
385 ms |
7416 KB |
Output is correct |
15 |
Correct |
398 ms |
7380 KB |
Output is correct |
16 |
Correct |
75 ms |
5716 KB |
Output is correct |
17 |
Correct |
83 ms |
5712 KB |
Output is correct |
18 |
Correct |
80 ms |
5772 KB |
Output is correct |
19 |
Correct |
81 ms |
6104 KB |
Output is correct |
20 |
Correct |
80 ms |
5712 KB |
Output is correct |
21 |
Correct |
435 ms |
7248 KB |
Output is correct |
22 |
Correct |
418 ms |
7252 KB |
Output is correct |
23 |
Correct |
413 ms |
7252 KB |
Output is correct |
24 |
Correct |
410 ms |
7248 KB |
Output is correct |
25 |
Correct |
420 ms |
7252 KB |
Output is correct |
26 |
Correct |
477 ms |
7188 KB |
Output is correct |
27 |
Correct |
483 ms |
7052 KB |
Output is correct |
28 |
Correct |
485 ms |
7000 KB |
Output is correct |
29 |
Correct |
460 ms |
7096 KB |
Output is correct |
30 |
Correct |
399 ms |
7324 KB |
Output is correct |
31 |
Correct |
395 ms |
7244 KB |
Output is correct |
32 |
Correct |
403 ms |
7248 KB |
Output is correct |
33 |
Correct |
390 ms |
7248 KB |
Output is correct |
34 |
Correct |
407 ms |
7252 KB |
Output is correct |
35 |
Correct |
412 ms |
7376 KB |
Output is correct |
36 |
Correct |
406 ms |
7420 KB |
Output is correct |
37 |
Correct |
407 ms |
7248 KB |
Output is correct |
38 |
Correct |
417 ms |
7248 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
8 ms |
1880 KB |
Output is correct |
2 |
Correct |
9 ms |
1884 KB |
Output is correct |
3 |
Correct |
9 ms |
1744 KB |
Output is correct |
4 |
Correct |
8 ms |
1664 KB |
Output is correct |
5 |
Correct |
10 ms |
1884 KB |
Output is correct |
6 |
Correct |
9 ms |
1884 KB |
Output is correct |
7 |
Correct |
9 ms |
1880 KB |
Output is correct |
8 |
Correct |
9 ms |
1884 KB |
Output is correct |
9 |
Correct |
9 ms |
1884 KB |
Output is correct |
10 |
Correct |
10 ms |
1884 KB |
Output is correct |
11 |
Correct |
9 ms |
1748 KB |
Output is correct |
12 |
Correct |
9 ms |
1884 KB |
Output is correct |
13 |
Correct |
8 ms |
1628 KB |
Output is correct |
14 |
Correct |
9 ms |
1884 KB |
Output is correct |
15 |
Correct |
11 ms |
1892 KB |
Output is correct |
16 |
Correct |
5 ms |
1628 KB |
Output is correct |
17 |
Correct |
4 ms |
1604 KB |
Output is correct |
18 |
Correct |
5 ms |
1628 KB |
Output is correct |
19 |
Correct |
6 ms |
1536 KB |
Output is correct |
20 |
Correct |
4 ms |
1628 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
402 ms |
7252 KB |
Output is correct |
2 |
Correct |
417 ms |
7252 KB |
Output is correct |
3 |
Correct |
408 ms |
7248 KB |
Output is correct |
4 |
Correct |
425 ms |
7504 KB |
Output is correct |
5 |
Correct |
431 ms |
7252 KB |
Output is correct |
6 |
Correct |
396 ms |
7504 KB |
Output is correct |
7 |
Correct |
389 ms |
7344 KB |
Output is correct |
8 |
Correct |
401 ms |
7328 KB |
Output is correct |
9 |
Correct |
403 ms |
7504 KB |
Output is correct |
10 |
Correct |
389 ms |
7248 KB |
Output is correct |
11 |
Correct |
403 ms |
7268 KB |
Output is correct |
12 |
Correct |
401 ms |
7248 KB |
Output is correct |
13 |
Correct |
395 ms |
7252 KB |
Output is correct |
14 |
Correct |
385 ms |
7416 KB |
Output is correct |
15 |
Correct |
398 ms |
7380 KB |
Output is correct |
16 |
Correct |
75 ms |
5716 KB |
Output is correct |
17 |
Correct |
83 ms |
5712 KB |
Output is correct |
18 |
Correct |
80 ms |
5772 KB |
Output is correct |
19 |
Correct |
81 ms |
6104 KB |
Output is correct |
20 |
Correct |
80 ms |
5712 KB |
Output is correct |
21 |
Correct |
435 ms |
7248 KB |
Output is correct |
22 |
Correct |
418 ms |
7252 KB |
Output is correct |
23 |
Correct |
413 ms |
7252 KB |
Output is correct |
24 |
Correct |
410 ms |
7248 KB |
Output is correct |
25 |
Correct |
420 ms |
7252 KB |
Output is correct |
26 |
Correct |
477 ms |
7188 KB |
Output is correct |
27 |
Correct |
483 ms |
7052 KB |
Output is correct |
28 |
Correct |
485 ms |
7000 KB |
Output is correct |
29 |
Correct |
460 ms |
7096 KB |
Output is correct |
30 |
Correct |
399 ms |
7324 KB |
Output is correct |
31 |
Correct |
395 ms |
7244 KB |
Output is correct |
32 |
Correct |
403 ms |
7248 KB |
Output is correct |
33 |
Correct |
390 ms |
7248 KB |
Output is correct |
34 |
Correct |
407 ms |
7252 KB |
Output is correct |
35 |
Correct |
412 ms |
7376 KB |
Output is correct |
36 |
Correct |
406 ms |
7420 KB |
Output is correct |
37 |
Correct |
407 ms |
7248 KB |
Output is correct |
38 |
Correct |
417 ms |
7248 KB |
Output is correct |
39 |
Correct |
8 ms |
1880 KB |
Output is correct |
40 |
Correct |
9 ms |
1884 KB |
Output is correct |
41 |
Correct |
9 ms |
1744 KB |
Output is correct |
42 |
Correct |
8 ms |
1664 KB |
Output is correct |
43 |
Correct |
10 ms |
1884 KB |
Output is correct |
44 |
Correct |
9 ms |
1884 KB |
Output is correct |
45 |
Correct |
9 ms |
1880 KB |
Output is correct |
46 |
Correct |
9 ms |
1884 KB |
Output is correct |
47 |
Correct |
9 ms |
1884 KB |
Output is correct |
48 |
Correct |
10 ms |
1884 KB |
Output is correct |
49 |
Correct |
9 ms |
1748 KB |
Output is correct |
50 |
Correct |
9 ms |
1884 KB |
Output is correct |
51 |
Correct |
8 ms |
1628 KB |
Output is correct |
52 |
Correct |
9 ms |
1884 KB |
Output is correct |
53 |
Correct |
11 ms |
1892 KB |
Output is correct |
54 |
Correct |
5 ms |
1628 KB |
Output is correct |
55 |
Correct |
4 ms |
1604 KB |
Output is correct |
56 |
Correct |
5 ms |
1628 KB |
Output is correct |
57 |
Correct |
6 ms |
1536 KB |
Output is correct |
58 |
Correct |
4 ms |
1628 KB |
Output is correct |
59 |
Correct |
528 ms |
7316 KB |
Output is correct |
60 |
Correct |
530 ms |
7248 KB |
Output is correct |
61 |
Correct |
532 ms |
7248 KB |
Output is correct |
62 |
Correct |
538 ms |
7252 KB |
Output is correct |
63 |
Correct |
531 ms |
7248 KB |
Output is correct |
64 |
Correct |
630 ms |
7380 KB |
Output is correct |
65 |
Correct |
623 ms |
7348 KB |
Output is correct |
66 |
Correct |
621 ms |
7248 KB |
Output is correct |
67 |
Correct |
631 ms |
7424 KB |
Output is correct |
68 |
Correct |
626 ms |
7252 KB |
Output is correct |
69 |
Correct |
548 ms |
7244 KB |
Output is correct |
70 |
Correct |
559 ms |
7360 KB |
Output is correct |
71 |
Correct |
560 ms |
7508 KB |
Output is correct |
72 |
Correct |
563 ms |
7508 KB |
Output is correct |
73 |
Correct |
553 ms |
7252 KB |
Output is correct |
74 |
Correct |
95 ms |
5716 KB |
Output is correct |
75 |
Correct |
96 ms |
5660 KB |
Output is correct |
76 |
Correct |
96 ms |
5748 KB |
Output is correct |
77 |
Correct |
95 ms |
5716 KB |
Output is correct |
78 |
Correct |
92 ms |
5716 KB |
Output is correct |