#include<bits/stdc++.h>
#define M 1000000007
#define maxn 502
using namespace std;
typedef long long ll;
inline ll norm(ll a) {
return (a < 0 ? a + M : (a >= M ? a - M : a));
}
inline ll mul(ll a, ll b) {
return a * b % M;
}
ll power(ll a, ll b) {
if (b == 0) return 1;
if (b&1) return mul(power(a, b - 1), a);
ll t = power(a, b / 2);
return mul(t, t);
}
ll gt[maxn * 2], igt[maxn * 2];
void precalc(){
int n = 1000;
gt[0] = 1;
for (int i = 1; i <= n; ++i)
gt[i] = mul(gt[i - 1], i);
igt[n] = power(gt[n], M - 2);
for (int i = n - 1; i >= 0; --i)
igt[i] = mul(igt[i + 1], i + 1);
}
ll C(int n, int k) {
return mul(mul(gt[n], igt[k]), igt[n - k]);
}
int n;
int l[maxn], r[maxn];
vector < pair < int, int > > seg;
vector < vector < int > > a;
vector < int > leng;
ll dp[maxn * 4][maxn], sumk[maxn * 4];
int main(){
#define TASK "ABC"
// freopen(TASK".inp", "r", stdin); freopen(TASK".out", "w", stdout);
ios_base::sync_with_stdio(0);
precalc();
cin >> n;
vector < int > ret;
for (int i = 1; i <= n; ++i) {
cin >> l[i] >> r[i];
ret.push_back(l[i]);
ret.push_back(r[i]);
}
sort(ret.begin(), ret.end());
seg.push_back({ret[0], ret[0]});
for (int i = 1; i < ret.size(); ++i)
if (ret[i] != ret[i - 1]) {
if (ret[i - 1] + 1 != ret[i])
seg.push_back({ret[i - 1] + 1, ret[i] - 1});
seg.push_back({ret[i], ret[i]});
}
a = vector < vector < int > >(seg.size(), vector < int >(0, 0));
leng = vector < int > (seg.size(), 0);
for (int i = 0; i < seg.size(); ++i) {
for (int j = 1; j <= n; ++j)
if (l[j] <= seg[i].first && seg[i].second <= r[j])
a[i].push_back(j);
leng[i] = seg[i].second - seg[i].first + 1;
}
ll ans = 0;
sumk[0] = 1;
for (int i = 0; i < seg.size(); ++i) {
ll l = leng[i];
vector < ll > c(a[i].size() + 1, 0), val(a[i].size() + 1, 0);
c[0] = 1;
for (int k = 1; k <= a[i].size(); ++k) {
if (k <= l)
c[k] = mul(mul(c[k - 1], l - k + 1), power(k, M - 2));
for (int x = k; x > 0; --x)
if (x <= l)
val[k] = norm(val[k] + mul(c[x], C(k - 1, x - 1)));
}
int index = 0;
for (int k = 0; k <= n; ++k) {
if (i) sumk[k] = norm(sumk[k] + dp[i - 1][k]);
ll res = sumk[k];
while (index < a[i].size() && a[i][index] <= k)
index++;
for (int j = index; j < a[i].size(); ++j)
dp[i][a[i][j]] = norm(dp[i][a[i][j]] + mul(res, val[j - index + 1]));
ans = norm(ans + dp[i][k]);
}
}
cout << ans;
return 0;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:75:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 1; i < ret.size(); ++i)
~~^~~~~~~~~~~~
boat.cpp:85:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < seg.size(); ++i) {
~~^~~~~~~~~~~~
boat.cpp:96:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < seg.size(); ++i) {
~~^~~~~~~~~~~~
boat.cpp:103:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int k = 1; k <= a[i].size(); ++k) {
~~^~~~~~~~~~~~~~
boat.cpp:120:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
while (index < a[i].size() && a[i][index] <= k)
~~~~~~^~~~~~~~~~~~~
boat.cpp:123:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int j = index; j < a[i].size(); ++j)
~~^~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
10 ms |
2432 KB |
Output is correct |
2 |
Correct |
11 ms |
2432 KB |
Output is correct |
3 |
Correct |
10 ms |
2432 KB |
Output is correct |
4 |
Correct |
10 ms |
2432 KB |
Output is correct |
5 |
Correct |
10 ms |
2432 KB |
Output is correct |
6 |
Correct |
10 ms |
2432 KB |
Output is correct |
7 |
Correct |
10 ms |
2432 KB |
Output is correct |
8 |
Correct |
11 ms |
2432 KB |
Output is correct |
9 |
Correct |
10 ms |
2432 KB |
Output is correct |
10 |
Correct |
10 ms |
2432 KB |
Output is correct |
11 |
Correct |
11 ms |
2432 KB |
Output is correct |
12 |
Correct |
10 ms |
2432 KB |
Output is correct |
13 |
Correct |
10 ms |
2432 KB |
Output is correct |
14 |
Correct |
10 ms |
2432 KB |
Output is correct |
15 |
Correct |
10 ms |
2432 KB |
Output is correct |
16 |
Correct |
6 ms |
896 KB |
Output is correct |
17 |
Correct |
6 ms |
896 KB |
Output is correct |
18 |
Correct |
6 ms |
1024 KB |
Output is correct |
19 |
Correct |
7 ms |
1024 KB |
Output is correct |
20 |
Correct |
7 ms |
896 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
10 ms |
2432 KB |
Output is correct |
2 |
Correct |
11 ms |
2432 KB |
Output is correct |
3 |
Correct |
10 ms |
2432 KB |
Output is correct |
4 |
Correct |
10 ms |
2432 KB |
Output is correct |
5 |
Correct |
10 ms |
2432 KB |
Output is correct |
6 |
Correct |
10 ms |
2432 KB |
Output is correct |
7 |
Correct |
10 ms |
2432 KB |
Output is correct |
8 |
Correct |
11 ms |
2432 KB |
Output is correct |
9 |
Correct |
10 ms |
2432 KB |
Output is correct |
10 |
Correct |
10 ms |
2432 KB |
Output is correct |
11 |
Correct |
11 ms |
2432 KB |
Output is correct |
12 |
Correct |
10 ms |
2432 KB |
Output is correct |
13 |
Correct |
10 ms |
2432 KB |
Output is correct |
14 |
Correct |
10 ms |
2432 KB |
Output is correct |
15 |
Correct |
10 ms |
2432 KB |
Output is correct |
16 |
Correct |
6 ms |
896 KB |
Output is correct |
17 |
Correct |
6 ms |
896 KB |
Output is correct |
18 |
Correct |
6 ms |
1024 KB |
Output is correct |
19 |
Correct |
7 ms |
1024 KB |
Output is correct |
20 |
Correct |
7 ms |
896 KB |
Output is correct |
21 |
Correct |
366 ms |
8492 KB |
Output is correct |
22 |
Correct |
352 ms |
8568 KB |
Output is correct |
23 |
Correct |
331 ms |
8440 KB |
Output is correct |
24 |
Correct |
357 ms |
8568 KB |
Output is correct |
25 |
Correct |
349 ms |
8312 KB |
Output is correct |
26 |
Correct |
484 ms |
8696 KB |
Output is correct |
27 |
Correct |
493 ms |
8824 KB |
Output is correct |
28 |
Correct |
488 ms |
8824 KB |
Output is correct |
29 |
Correct |
491 ms |
8864 KB |
Output is correct |
30 |
Correct |
20 ms |
7808 KB |
Output is correct |
31 |
Correct |
20 ms |
7680 KB |
Output is correct |
32 |
Correct |
19 ms |
7680 KB |
Output is correct |
33 |
Correct |
19 ms |
7808 KB |
Output is correct |
34 |
Correct |
21 ms |
7808 KB |
Output is correct |
35 |
Correct |
13 ms |
4352 KB |
Output is correct |
36 |
Correct |
13 ms |
4352 KB |
Output is correct |
37 |
Correct |
14 ms |
4352 KB |
Output is correct |
38 |
Correct |
13 ms |
4352 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
12 ms |
2048 KB |
Output is correct |
2 |
Correct |
11 ms |
2048 KB |
Output is correct |
3 |
Correct |
12 ms |
2048 KB |
Output is correct |
4 |
Correct |
12 ms |
2048 KB |
Output is correct |
5 |
Correct |
13 ms |
2048 KB |
Output is correct |
6 |
Correct |
16 ms |
2048 KB |
Output is correct |
7 |
Correct |
17 ms |
2048 KB |
Output is correct |
8 |
Correct |
16 ms |
2048 KB |
Output is correct |
9 |
Correct |
17 ms |
2048 KB |
Output is correct |
10 |
Correct |
16 ms |
2048 KB |
Output is correct |
11 |
Correct |
13 ms |
2048 KB |
Output is correct |
12 |
Correct |
11 ms |
2048 KB |
Output is correct |
13 |
Correct |
12 ms |
2048 KB |
Output is correct |
14 |
Correct |
12 ms |
2048 KB |
Output is correct |
15 |
Correct |
13 ms |
2048 KB |
Output is correct |
16 |
Correct |
8 ms |
1024 KB |
Output is correct |
17 |
Correct |
8 ms |
1024 KB |
Output is correct |
18 |
Correct |
8 ms |
1024 KB |
Output is correct |
19 |
Correct |
8 ms |
1024 KB |
Output is correct |
20 |
Correct |
9 ms |
1152 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
10 ms |
2432 KB |
Output is correct |
2 |
Correct |
11 ms |
2432 KB |
Output is correct |
3 |
Correct |
10 ms |
2432 KB |
Output is correct |
4 |
Correct |
10 ms |
2432 KB |
Output is correct |
5 |
Correct |
10 ms |
2432 KB |
Output is correct |
6 |
Correct |
10 ms |
2432 KB |
Output is correct |
7 |
Correct |
10 ms |
2432 KB |
Output is correct |
8 |
Correct |
11 ms |
2432 KB |
Output is correct |
9 |
Correct |
10 ms |
2432 KB |
Output is correct |
10 |
Correct |
10 ms |
2432 KB |
Output is correct |
11 |
Correct |
11 ms |
2432 KB |
Output is correct |
12 |
Correct |
10 ms |
2432 KB |
Output is correct |
13 |
Correct |
10 ms |
2432 KB |
Output is correct |
14 |
Correct |
10 ms |
2432 KB |
Output is correct |
15 |
Correct |
10 ms |
2432 KB |
Output is correct |
16 |
Correct |
6 ms |
896 KB |
Output is correct |
17 |
Correct |
6 ms |
896 KB |
Output is correct |
18 |
Correct |
6 ms |
1024 KB |
Output is correct |
19 |
Correct |
7 ms |
1024 KB |
Output is correct |
20 |
Correct |
7 ms |
896 KB |
Output is correct |
21 |
Correct |
366 ms |
8492 KB |
Output is correct |
22 |
Correct |
352 ms |
8568 KB |
Output is correct |
23 |
Correct |
331 ms |
8440 KB |
Output is correct |
24 |
Correct |
357 ms |
8568 KB |
Output is correct |
25 |
Correct |
349 ms |
8312 KB |
Output is correct |
26 |
Correct |
484 ms |
8696 KB |
Output is correct |
27 |
Correct |
493 ms |
8824 KB |
Output is correct |
28 |
Correct |
488 ms |
8824 KB |
Output is correct |
29 |
Correct |
491 ms |
8864 KB |
Output is correct |
30 |
Correct |
20 ms |
7808 KB |
Output is correct |
31 |
Correct |
20 ms |
7680 KB |
Output is correct |
32 |
Correct |
19 ms |
7680 KB |
Output is correct |
33 |
Correct |
19 ms |
7808 KB |
Output is correct |
34 |
Correct |
21 ms |
7808 KB |
Output is correct |
35 |
Correct |
13 ms |
4352 KB |
Output is correct |
36 |
Correct |
13 ms |
4352 KB |
Output is correct |
37 |
Correct |
14 ms |
4352 KB |
Output is correct |
38 |
Correct |
13 ms |
4352 KB |
Output is correct |
39 |
Correct |
12 ms |
2048 KB |
Output is correct |
40 |
Correct |
11 ms |
2048 KB |
Output is correct |
41 |
Correct |
12 ms |
2048 KB |
Output is correct |
42 |
Correct |
12 ms |
2048 KB |
Output is correct |
43 |
Correct |
13 ms |
2048 KB |
Output is correct |
44 |
Correct |
16 ms |
2048 KB |
Output is correct |
45 |
Correct |
17 ms |
2048 KB |
Output is correct |
46 |
Correct |
16 ms |
2048 KB |
Output is correct |
47 |
Correct |
17 ms |
2048 KB |
Output is correct |
48 |
Correct |
16 ms |
2048 KB |
Output is correct |
49 |
Correct |
13 ms |
2048 KB |
Output is correct |
50 |
Correct |
11 ms |
2048 KB |
Output is correct |
51 |
Correct |
12 ms |
2048 KB |
Output is correct |
52 |
Correct |
12 ms |
2048 KB |
Output is correct |
53 |
Correct |
13 ms |
2048 KB |
Output is correct |
54 |
Correct |
8 ms |
1024 KB |
Output is correct |
55 |
Correct |
8 ms |
1024 KB |
Output is correct |
56 |
Correct |
8 ms |
1024 KB |
Output is correct |
57 |
Correct |
8 ms |
1024 KB |
Output is correct |
58 |
Correct |
9 ms |
1152 KB |
Output is correct |
59 |
Correct |
623 ms |
10116 KB |
Output is correct |
60 |
Correct |
566 ms |
9980 KB |
Output is correct |
61 |
Correct |
533 ms |
9976 KB |
Output is correct |
62 |
Correct |
611 ms |
10232 KB |
Output is correct |
63 |
Correct |
596 ms |
9980 KB |
Output is correct |
64 |
Correct |
1004 ms |
11064 KB |
Output is correct |
65 |
Correct |
1002 ms |
11076 KB |
Output is correct |
66 |
Correct |
997 ms |
10976 KB |
Output is correct |
67 |
Correct |
995 ms |
10912 KB |
Output is correct |
68 |
Correct |
991 ms |
11128 KB |
Output is correct |
69 |
Correct |
480 ms |
9848 KB |
Output is correct |
70 |
Correct |
484 ms |
10024 KB |
Output is correct |
71 |
Correct |
476 ms |
9976 KB |
Output is correct |
72 |
Correct |
499 ms |
9976 KB |
Output is correct |
73 |
Correct |
504 ms |
9976 KB |
Output is correct |
74 |
Correct |
66 ms |
1400 KB |
Output is correct |
75 |
Correct |
61 ms |
1348 KB |
Output is correct |
76 |
Correct |
64 ms |
1400 KB |
Output is correct |
77 |
Correct |
67 ms |
1400 KB |
Output is correct |
78 |
Correct |
66 ms |
1400 KB |
Output is correct |