#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll mod = 1e9 + 7;
ll pref[505][1005], ia[505];
ll pwr(ll a, ll b){
ll ans = 1;
while (b){
if (b & 1) ans = ans * a % mod;
a = a * a % mod;
b >>= 1;
}
return ans;
}
ll inv(ll a){
return pwr(a, mod - 2);
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int nums; cin >> nums;
for (int i = 1; i <= nums; i++) ia[i] = inv(i);
vector<ll> av(nums + 1), bv(nums + 1), disc; disc.push_back(-1);
for (int i = 1; i <= nums; i++){
ll a, b; cin >> a >> b; b++;
av[i] = a; bv[i] = b;
disc.push_back(a); disc.push_back(b);
}
sort(disc.begin(), disc.end());
disc.resize(distance(disc.begin(), unique(disc.begin(), disc.end())));
int segs = disc.size() - 2;
for (int j = 0; j <= segs; j++) pref[0][j] = 1;
ll ans = 0;
for (int i = 1; i <= nums; i++)
for (int j = 1; j <= segs; j++){
ll dpv = 0, len = disc[j + 1] - disc[j];
if (av[i] <= disc[j] && bv[i] >= disc[j + 1]){
ll cv = len; int cnt = 1;
for (int k = i - 1; k >= 0; k--){
dpv = (dpv + pref[k][j - 1] * cv % mod) % mod;
if (av[k] <= disc[j] && bv[k] >= disc[j + 1]){
cnt++; cv = cv * (len + cnt - 1) % mod * ia[cnt] % mod;
}
}
}
pref[i][j] = (pref[i][j - 1] + dpv) % mod;
ans = (ans + dpv) % mod;
}
cout << ans;
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
4 ms |
4184 KB |
Output is correct |
| 2 |
Correct |
4 ms |
4184 KB |
Output is correct |
| 3 |
Correct |
5 ms |
4284 KB |
Output is correct |
| 4 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 5 |
Correct |
5 ms |
4444 KB |
Output is correct |
| 6 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 7 |
Correct |
5 ms |
4444 KB |
Output is correct |
| 8 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 9 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 10 |
Correct |
4 ms |
4184 KB |
Output is correct |
| 11 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 12 |
Correct |
4 ms |
4280 KB |
Output is correct |
| 13 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 14 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 15 |
Correct |
5 ms |
4312 KB |
Output is correct |
| 16 |
Correct |
3 ms |
3032 KB |
Output is correct |
| 17 |
Correct |
3 ms |
3160 KB |
Output is correct |
| 18 |
Correct |
3 ms |
3032 KB |
Output is correct |
| 19 |
Correct |
3 ms |
3160 KB |
Output is correct |
| 20 |
Correct |
3 ms |
3160 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
4 ms |
4184 KB |
Output is correct |
| 2 |
Correct |
4 ms |
4184 KB |
Output is correct |
| 3 |
Correct |
5 ms |
4284 KB |
Output is correct |
| 4 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 5 |
Correct |
5 ms |
4444 KB |
Output is correct |
| 6 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 7 |
Correct |
5 ms |
4444 KB |
Output is correct |
| 8 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 9 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 10 |
Correct |
4 ms |
4184 KB |
Output is correct |
| 11 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 12 |
Correct |
4 ms |
4280 KB |
Output is correct |
| 13 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 14 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 15 |
Correct |
5 ms |
4312 KB |
Output is correct |
| 16 |
Correct |
3 ms |
3032 KB |
Output is correct |
| 17 |
Correct |
3 ms |
3160 KB |
Output is correct |
| 18 |
Correct |
3 ms |
3032 KB |
Output is correct |
| 19 |
Correct |
3 ms |
3160 KB |
Output is correct |
| 20 |
Correct |
3 ms |
3160 KB |
Output is correct |
| 21 |
Correct |
223 ms |
4332 KB |
Output is correct |
| 22 |
Correct |
218 ms |
4244 KB |
Output is correct |
| 23 |
Correct |
191 ms |
4252 KB |
Output is correct |
| 24 |
Correct |
209 ms |
4176 KB |
Output is correct |
| 25 |
Correct |
222 ms |
4556 KB |
Output is correct |
| 26 |
Correct |
416 ms |
4432 KB |
Output is correct |
| 27 |
Correct |
429 ms |
4176 KB |
Output is correct |
| 28 |
Correct |
420 ms |
4212 KB |
Output is correct |
| 29 |
Correct |
412 ms |
4176 KB |
Output is correct |
| 30 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 31 |
Correct |
5 ms |
4184 KB |
Output is correct |
| 32 |
Correct |
6 ms |
4188 KB |
Output is correct |
| 33 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 34 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 35 |
Correct |
6 ms |
4188 KB |
Output is correct |
| 36 |
Correct |
6 ms |
4452 KB |
Output is correct |
| 37 |
Correct |
6 ms |
4308 KB |
Output is correct |
| 38 |
Correct |
6 ms |
4444 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
3 ms |
860 KB |
Output is correct |
| 2 |
Correct |
2 ms |
860 KB |
Output is correct |
| 3 |
Correct |
2 ms |
860 KB |
Output is correct |
| 4 |
Correct |
3 ms |
860 KB |
Output is correct |
| 5 |
Correct |
3 ms |
860 KB |
Output is correct |
| 6 |
Correct |
4 ms |
860 KB |
Output is correct |
| 7 |
Correct |
4 ms |
860 KB |
Output is correct |
| 8 |
Correct |
4 ms |
860 KB |
Output is correct |
| 9 |
Correct |
4 ms |
860 KB |
Output is correct |
| 10 |
Correct |
5 ms |
860 KB |
Output is correct |
| 11 |
Correct |
3 ms |
860 KB |
Output is correct |
| 12 |
Correct |
3 ms |
860 KB |
Output is correct |
| 13 |
Correct |
3 ms |
860 KB |
Output is correct |
| 14 |
Correct |
2 ms |
860 KB |
Output is correct |
| 15 |
Correct |
3 ms |
860 KB |
Output is correct |
| 16 |
Correct |
2 ms |
860 KB |
Output is correct |
| 17 |
Correct |
2 ms |
860 KB |
Output is correct |
| 18 |
Correct |
2 ms |
860 KB |
Output is correct |
| 19 |
Correct |
2 ms |
856 KB |
Output is correct |
| 20 |
Correct |
2 ms |
860 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
4 ms |
4184 KB |
Output is correct |
| 2 |
Correct |
4 ms |
4184 KB |
Output is correct |
| 3 |
Correct |
5 ms |
4284 KB |
Output is correct |
| 4 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 5 |
Correct |
5 ms |
4444 KB |
Output is correct |
| 6 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 7 |
Correct |
5 ms |
4444 KB |
Output is correct |
| 8 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 9 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 10 |
Correct |
4 ms |
4184 KB |
Output is correct |
| 11 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 12 |
Correct |
4 ms |
4280 KB |
Output is correct |
| 13 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 14 |
Correct |
4 ms |
4188 KB |
Output is correct |
| 15 |
Correct |
5 ms |
4312 KB |
Output is correct |
| 16 |
Correct |
3 ms |
3032 KB |
Output is correct |
| 17 |
Correct |
3 ms |
3160 KB |
Output is correct |
| 18 |
Correct |
3 ms |
3032 KB |
Output is correct |
| 19 |
Correct |
3 ms |
3160 KB |
Output is correct |
| 20 |
Correct |
3 ms |
3160 KB |
Output is correct |
| 21 |
Correct |
223 ms |
4332 KB |
Output is correct |
| 22 |
Correct |
218 ms |
4244 KB |
Output is correct |
| 23 |
Correct |
191 ms |
4252 KB |
Output is correct |
| 24 |
Correct |
209 ms |
4176 KB |
Output is correct |
| 25 |
Correct |
222 ms |
4556 KB |
Output is correct |
| 26 |
Correct |
416 ms |
4432 KB |
Output is correct |
| 27 |
Correct |
429 ms |
4176 KB |
Output is correct |
| 28 |
Correct |
420 ms |
4212 KB |
Output is correct |
| 29 |
Correct |
412 ms |
4176 KB |
Output is correct |
| 30 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 31 |
Correct |
5 ms |
4184 KB |
Output is correct |
| 32 |
Correct |
6 ms |
4188 KB |
Output is correct |
| 33 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 34 |
Correct |
5 ms |
4188 KB |
Output is correct |
| 35 |
Correct |
6 ms |
4188 KB |
Output is correct |
| 36 |
Correct |
6 ms |
4452 KB |
Output is correct |
| 37 |
Correct |
6 ms |
4308 KB |
Output is correct |
| 38 |
Correct |
6 ms |
4444 KB |
Output is correct |
| 39 |
Correct |
3 ms |
860 KB |
Output is correct |
| 40 |
Correct |
2 ms |
860 KB |
Output is correct |
| 41 |
Correct |
2 ms |
860 KB |
Output is correct |
| 42 |
Correct |
3 ms |
860 KB |
Output is correct |
| 43 |
Correct |
3 ms |
860 KB |
Output is correct |
| 44 |
Correct |
4 ms |
860 KB |
Output is correct |
| 45 |
Correct |
4 ms |
860 KB |
Output is correct |
| 46 |
Correct |
4 ms |
860 KB |
Output is correct |
| 47 |
Correct |
4 ms |
860 KB |
Output is correct |
| 48 |
Correct |
5 ms |
860 KB |
Output is correct |
| 49 |
Correct |
3 ms |
860 KB |
Output is correct |
| 50 |
Correct |
3 ms |
860 KB |
Output is correct |
| 51 |
Correct |
3 ms |
860 KB |
Output is correct |
| 52 |
Correct |
2 ms |
860 KB |
Output is correct |
| 53 |
Correct |
3 ms |
860 KB |
Output is correct |
| 54 |
Correct |
2 ms |
860 KB |
Output is correct |
| 55 |
Correct |
2 ms |
860 KB |
Output is correct |
| 56 |
Correct |
2 ms |
860 KB |
Output is correct |
| 57 |
Correct |
2 ms |
856 KB |
Output is correct |
| 58 |
Correct |
2 ms |
860 KB |
Output is correct |
| 59 |
Correct |
252 ms |
4464 KB |
Output is correct |
| 60 |
Correct |
229 ms |
4252 KB |
Output is correct |
| 61 |
Correct |
209 ms |
4332 KB |
Output is correct |
| 62 |
Correct |
246 ms |
4276 KB |
Output is correct |
| 63 |
Correct |
231 ms |
4180 KB |
Output is correct |
| 64 |
Correct |
474 ms |
4520 KB |
Output is correct |
| 65 |
Correct |
476 ms |
4280 KB |
Output is correct |
| 66 |
Correct |
475 ms |
4400 KB |
Output is correct |
| 67 |
Correct |
483 ms |
4288 KB |
Output is correct |
| 68 |
Correct |
484 ms |
4280 KB |
Output is correct |
| 69 |
Correct |
195 ms |
4236 KB |
Output is correct |
| 70 |
Correct |
193 ms |
4304 KB |
Output is correct |
| 71 |
Correct |
189 ms |
4180 KB |
Output is correct |
| 72 |
Correct |
201 ms |
4236 KB |
Output is correct |
| 73 |
Correct |
202 ms |
4236 KB |
Output is correct |
| 74 |
Correct |
50 ms |
3112 KB |
Output is correct |
| 75 |
Correct |
47 ms |
3156 KB |
Output is correct |
| 76 |
Correct |
51 ms |
3156 KB |
Output is correct |
| 77 |
Correct |
51 ms |
3024 KB |
Output is correct |
| 78 |
Correct |
53 ms |
3088 KB |
Output is correct |
