#include <cstdio>
#include <algorithm>
const int md = 1000000007;
inline int add(int a, int b)
{
a += b;
if (a >= md) a -= md;
return a;
}
inline int sub(int a, int b)
{
a -= b;
if (a < 0) a += md;
return a;
}
inline int mul(int a, int b)
{
return (long long)a * b % md;
}
int po(int a, int b)
{
int r = 1;
while (b) {
if (b & 1) r = mul(r, a);
a = mul(a, a);
b >>= 1;
}
return r;
}
inline int inv(int a)
{
return po(a, md - 2);
}
inline int di(int a, int b)
{
return mul(a, inv(b));
}
const int N = 505;
int n, d[N << 1], l[N], r[N], a[N << 1], p[N << 1][N], amt[N << 1], ncr[N << 1][N];
int main()
{
scanf("%d", &n);
for (int i = 0; i < n; ++i) {
scanf("%d%d", l + i, r + i);
a[i << 1] = l[i];
a[i << 1 | 1] = r[i] + 1;
}
std::sort(a, a + n * 2);
int len = std::unique(a, a + n * 2) - a;
d[0] = 1;
for (int i = 0; i < n; ++i) {
for (int j = len - 1; j >= 1; --j) if (l[i] <= a[j - 1] && r[i] >= a[j] - 1) {
if (!amt[j]) ncr[j][0] = a[j] - a[j - 1];
else ncr[j][amt[j]] = di(mul(ncr[j][amt[j] - 1], ncr[j][0] - amt[j]), amt[j] + 1);
for (int k = amt[j]; k > 0; --k) {
p[j][k] = add(p[j][k], p[j][k - 1]);
d[j] = add(d[j], mul(p[j][k - 1], ncr[j][k]));
}
for (int k = 0; k < j; ++k) {
p[j][0] = add(p[j][0], d[k]);
d[j] = add(d[j], mul(ncr[j][0], d[k]));
}
++amt[j];
}
}
int ans = 0;
for (int i = 1; i < len; ++i) ans = add(ans, d[i]);
printf("%d\n", ans);
return 0;
}
Compilation message
boat.cpp: In function 'int main()':
boat.cpp:46:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
46 | scanf("%d", &n);
| ~~~~~^~~~~~~~~~
boat.cpp:48:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
48 | scanf("%d%d", l + i, r + i);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 2 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 3 |
Correct |
4 ms |
4160 KB |
Output is correct |
| 4 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 5 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 6 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 7 |
Correct |
4 ms |
4176 KB |
Output is correct |
| 8 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 9 |
Correct |
5 ms |
4172 KB |
Output is correct |
| 10 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 11 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 12 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 13 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 14 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 15 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 16 |
Correct |
1 ms |
972 KB |
Output is correct |
| 17 |
Correct |
1 ms |
972 KB |
Output is correct |
| 18 |
Correct |
2 ms |
972 KB |
Output is correct |
| 19 |
Correct |
1 ms |
972 KB |
Output is correct |
| 20 |
Correct |
1 ms |
972 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 2 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 3 |
Correct |
4 ms |
4160 KB |
Output is correct |
| 4 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 5 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 6 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 7 |
Correct |
4 ms |
4176 KB |
Output is correct |
| 8 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 9 |
Correct |
5 ms |
4172 KB |
Output is correct |
| 10 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 11 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 12 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 13 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 14 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 15 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 16 |
Correct |
1 ms |
972 KB |
Output is correct |
| 17 |
Correct |
1 ms |
972 KB |
Output is correct |
| 18 |
Correct |
2 ms |
972 KB |
Output is correct |
| 19 |
Correct |
1 ms |
972 KB |
Output is correct |
| 20 |
Correct |
1 ms |
972 KB |
Output is correct |
| 21 |
Correct |
355 ms |
3876 KB |
Output is correct |
| 22 |
Correct |
344 ms |
4052 KB |
Output is correct |
| 23 |
Correct |
316 ms |
3864 KB |
Output is correct |
| 24 |
Correct |
338 ms |
3836 KB |
Output is correct |
| 25 |
Correct |
350 ms |
3860 KB |
Output is correct |
| 26 |
Correct |
524 ms |
3804 KB |
Output is correct |
| 27 |
Correct |
551 ms |
3804 KB |
Output is correct |
| 28 |
Correct |
537 ms |
3648 KB |
Output is correct |
| 29 |
Correct |
526 ms |
3740 KB |
Output is correct |
| 30 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 31 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 32 |
Correct |
6 ms |
4136 KB |
Output is correct |
| 33 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 34 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 35 |
Correct |
6 ms |
4132 KB |
Output is correct |
| 36 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 37 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 38 |
Correct |
7 ms |
4172 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
5 ms |
972 KB |
Output is correct |
| 2 |
Correct |
4 ms |
972 KB |
Output is correct |
| 3 |
Correct |
5 ms |
972 KB |
Output is correct |
| 4 |
Correct |
5 ms |
1100 KB |
Output is correct |
| 5 |
Correct |
5 ms |
1100 KB |
Output is correct |
| 6 |
Correct |
8 ms |
1056 KB |
Output is correct |
| 7 |
Correct |
8 ms |
1100 KB |
Output is correct |
| 8 |
Correct |
8 ms |
1100 KB |
Output is correct |
| 9 |
Correct |
8 ms |
1056 KB |
Output is correct |
| 10 |
Correct |
8 ms |
1100 KB |
Output is correct |
| 11 |
Correct |
5 ms |
1100 KB |
Output is correct |
| 12 |
Correct |
6 ms |
1096 KB |
Output is correct |
| 13 |
Correct |
5 ms |
972 KB |
Output is correct |
| 14 |
Correct |
5 ms |
1100 KB |
Output is correct |
| 15 |
Correct |
5 ms |
972 KB |
Output is correct |
| 16 |
Correct |
3 ms |
716 KB |
Output is correct |
| 17 |
Correct |
3 ms |
668 KB |
Output is correct |
| 18 |
Correct |
2 ms |
716 KB |
Output is correct |
| 19 |
Correct |
3 ms |
756 KB |
Output is correct |
| 20 |
Correct |
3 ms |
716 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 2 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 3 |
Correct |
4 ms |
4160 KB |
Output is correct |
| 4 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 5 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 6 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 7 |
Correct |
4 ms |
4176 KB |
Output is correct |
| 8 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 9 |
Correct |
5 ms |
4172 KB |
Output is correct |
| 10 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 11 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 12 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 13 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 14 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 15 |
Correct |
4 ms |
4172 KB |
Output is correct |
| 16 |
Correct |
1 ms |
972 KB |
Output is correct |
| 17 |
Correct |
1 ms |
972 KB |
Output is correct |
| 18 |
Correct |
2 ms |
972 KB |
Output is correct |
| 19 |
Correct |
1 ms |
972 KB |
Output is correct |
| 20 |
Correct |
1 ms |
972 KB |
Output is correct |
| 21 |
Correct |
355 ms |
3876 KB |
Output is correct |
| 22 |
Correct |
344 ms |
4052 KB |
Output is correct |
| 23 |
Correct |
316 ms |
3864 KB |
Output is correct |
| 24 |
Correct |
338 ms |
3836 KB |
Output is correct |
| 25 |
Correct |
350 ms |
3860 KB |
Output is correct |
| 26 |
Correct |
524 ms |
3804 KB |
Output is correct |
| 27 |
Correct |
551 ms |
3804 KB |
Output is correct |
| 28 |
Correct |
537 ms |
3648 KB |
Output is correct |
| 29 |
Correct |
526 ms |
3740 KB |
Output is correct |
| 30 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 31 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 32 |
Correct |
6 ms |
4136 KB |
Output is correct |
| 33 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 34 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 35 |
Correct |
6 ms |
4132 KB |
Output is correct |
| 36 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 37 |
Correct |
6 ms |
4172 KB |
Output is correct |
| 38 |
Correct |
7 ms |
4172 KB |
Output is correct |
| 39 |
Correct |
5 ms |
972 KB |
Output is correct |
| 40 |
Correct |
4 ms |
972 KB |
Output is correct |
| 41 |
Correct |
5 ms |
972 KB |
Output is correct |
| 42 |
Correct |
5 ms |
1100 KB |
Output is correct |
| 43 |
Correct |
5 ms |
1100 KB |
Output is correct |
| 44 |
Correct |
8 ms |
1056 KB |
Output is correct |
| 45 |
Correct |
8 ms |
1100 KB |
Output is correct |
| 46 |
Correct |
8 ms |
1100 KB |
Output is correct |
| 47 |
Correct |
8 ms |
1056 KB |
Output is correct |
| 48 |
Correct |
8 ms |
1100 KB |
Output is correct |
| 49 |
Correct |
5 ms |
1100 KB |
Output is correct |
| 50 |
Correct |
6 ms |
1096 KB |
Output is correct |
| 51 |
Correct |
5 ms |
972 KB |
Output is correct |
| 52 |
Correct |
5 ms |
1100 KB |
Output is correct |
| 53 |
Correct |
5 ms |
972 KB |
Output is correct |
| 54 |
Correct |
3 ms |
716 KB |
Output is correct |
| 55 |
Correct |
3 ms |
668 KB |
Output is correct |
| 56 |
Correct |
2 ms |
716 KB |
Output is correct |
| 57 |
Correct |
3 ms |
756 KB |
Output is correct |
| 58 |
Correct |
3 ms |
716 KB |
Output is correct |
| 59 |
Correct |
413 ms |
4216 KB |
Output is correct |
| 60 |
Correct |
387 ms |
4232 KB |
Output is correct |
| 61 |
Correct |
383 ms |
4232 KB |
Output is correct |
| 62 |
Correct |
422 ms |
4232 KB |
Output is correct |
| 63 |
Correct |
402 ms |
4232 KB |
Output is correct |
| 64 |
Correct |
661 ms |
4164 KB |
Output is correct |
| 65 |
Correct |
659 ms |
4372 KB |
Output is correct |
| 66 |
Correct |
698 ms |
4244 KB |
Output is correct |
| 67 |
Correct |
689 ms |
4140 KB |
Output is correct |
| 68 |
Correct |
684 ms |
4160 KB |
Output is correct |
| 69 |
Correct |
372 ms |
4236 KB |
Output is correct |
| 70 |
Correct |
376 ms |
4236 KB |
Output is correct |
| 71 |
Correct |
409 ms |
4232 KB |
Output is correct |
| 72 |
Correct |
426 ms |
4160 KB |
Output is correct |
| 73 |
Correct |
401 ms |
4232 KB |
Output is correct |
| 74 |
Correct |
32 ms |
932 KB |
Output is correct |
| 75 |
Correct |
31 ms |
972 KB |
Output is correct |
| 76 |
Correct |
32 ms |
972 KB |
Output is correct |
| 77 |
Correct |
43 ms |
1032 KB |
Output is correct |
| 78 |
Correct |
32 ms |
1000 KB |
Output is correct |
