#include <bits/stdc++.h>
using namespace std;
const int N = 505, mod = 1e9 + 7;
int n, m, a[N], b[N], cnt[N * 2], dp[N * 2][N], inv[N];
vector<int> v, f;
signed main(){
cin.tie(0), cout.tie(0) -> sync_with_stdio(0);
cin >> n;
for (int i = 1; i <= n; i++)
cin >> a[i] >> b[i], b[i] ++;
inv[1] = 1;
for (int i = 2; i <= n; i++)
inv[i] = mod - 1ll * (mod / i) * inv[mod % i] % mod;
for (int i = 1; i <= n; i++)
v.push_back(a[i]), v.push_back(b[i]);
sort(v.begin(), v.end());
v.erase(unique(v.begin(), v.end()), v.end());
f.resize(m = v.size() - 1);
for (int i = 1; i < (int) v.size(); i++)
f[i - 1] = v[i] - v[i - 1];
for (int i = 1; i <= n; i++) {
int l = lower_bound(v.begin(), v.end(), a[i]) - v.begin(), r = lower_bound(v.begin(), v.end(), b[i]) - v.begin(), cur = 1;
for (int j = 0; j < l; j++) {
for (int k = cnt[j]; k; k--)
if ((cur += dp[j][k]) >= mod)
cur -= mod;
}
for (int j = l; j < r; j++) {
int nxt = cur;
for (int k = cnt[j]; k; k--) {
if ((nxt += dp[j][k]) >= mod)
nxt -= mod;
dp[j][k + 1] += 1ll * dp[j][k] * (f[j] - k) % mod * inv[k + 1] % mod;
if (dp[j][k + 1] >= mod) dp[j][k + 1] -= mod;
}
++ cnt[j];
dp[j][1] += 1ll * cur * f[j] % mod;
if (dp[j][1] >= mod) dp[j][1] -= mod;
swap(nxt, cur);
}
}
int res = 0;
for (int j = 0; j < m; j++)
for (int k = 1; k <= cnt[j]; k++)
if ((res += dp[j][k]) >= mod)
res -= mod;
cout << res << '\n';
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 2 |
Correct |
3 ms |
2264 KB |
Output is correct |
| 3 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 4 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 5 |
Correct |
2 ms |
2256 KB |
Output is correct |
| 6 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 7 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 8 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 9 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 10 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 11 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 12 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 13 |
Correct |
2 ms |
2256 KB |
Output is correct |
| 14 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 15 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 16 |
Correct |
1 ms |
596 KB |
Output is correct |
| 17 |
Correct |
1 ms |
724 KB |
Output is correct |
| 18 |
Correct |
1 ms |
596 KB |
Output is correct |
| 19 |
Correct |
1 ms |
724 KB |
Output is correct |
| 20 |
Correct |
1 ms |
592 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 2 |
Correct |
3 ms |
2264 KB |
Output is correct |
| 3 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 4 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 5 |
Correct |
2 ms |
2256 KB |
Output is correct |
| 6 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 7 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 8 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 9 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 10 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 11 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 12 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 13 |
Correct |
2 ms |
2256 KB |
Output is correct |
| 14 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 15 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 16 |
Correct |
1 ms |
596 KB |
Output is correct |
| 17 |
Correct |
1 ms |
724 KB |
Output is correct |
| 18 |
Correct |
1 ms |
596 KB |
Output is correct |
| 19 |
Correct |
1 ms |
724 KB |
Output is correct |
| 20 |
Correct |
1 ms |
592 KB |
Output is correct |
| 21 |
Correct |
117 ms |
2148 KB |
Output is correct |
| 22 |
Correct |
112 ms |
2128 KB |
Output is correct |
| 23 |
Correct |
98 ms |
2128 KB |
Output is correct |
| 24 |
Correct |
146 ms |
2004 KB |
Output is correct |
| 25 |
Correct |
109 ms |
2132 KB |
Output is correct |
| 26 |
Correct |
231 ms |
2044 KB |
Output is correct |
| 27 |
Correct |
268 ms |
2124 KB |
Output is correct |
| 28 |
Correct |
242 ms |
2084 KB |
Output is correct |
| 29 |
Correct |
233 ms |
2020 KB |
Output is correct |
| 30 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 31 |
Correct |
3 ms |
2260 KB |
Output is correct |
| 32 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 33 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 34 |
Correct |
3 ms |
2272 KB |
Output is correct |
| 35 |
Correct |
3 ms |
2260 KB |
Output is correct |
| 36 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 37 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 38 |
Correct |
4 ms |
2260 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
724 KB |
Output is correct |
| 2 |
Correct |
2 ms |
724 KB |
Output is correct |
| 3 |
Correct |
2 ms |
724 KB |
Output is correct |
| 4 |
Correct |
2 ms |
724 KB |
Output is correct |
| 5 |
Correct |
2 ms |
724 KB |
Output is correct |
| 6 |
Correct |
4 ms |
716 KB |
Output is correct |
| 7 |
Correct |
3 ms |
724 KB |
Output is correct |
| 8 |
Correct |
3 ms |
724 KB |
Output is correct |
| 9 |
Correct |
3 ms |
724 KB |
Output is correct |
| 10 |
Correct |
4 ms |
724 KB |
Output is correct |
| 11 |
Correct |
2 ms |
732 KB |
Output is correct |
| 12 |
Correct |
2 ms |
716 KB |
Output is correct |
| 13 |
Correct |
2 ms |
724 KB |
Output is correct |
| 14 |
Correct |
2 ms |
724 KB |
Output is correct |
| 15 |
Correct |
2 ms |
724 KB |
Output is correct |
| 16 |
Correct |
1 ms |
468 KB |
Output is correct |
| 17 |
Correct |
1 ms |
468 KB |
Output is correct |
| 18 |
Correct |
2 ms |
468 KB |
Output is correct |
| 19 |
Correct |
1 ms |
468 KB |
Output is correct |
| 20 |
Correct |
1 ms |
468 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 2 |
Correct |
3 ms |
2264 KB |
Output is correct |
| 3 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 4 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 5 |
Correct |
2 ms |
2256 KB |
Output is correct |
| 6 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 7 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 8 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 9 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 10 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 11 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 12 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 13 |
Correct |
2 ms |
2256 KB |
Output is correct |
| 14 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 15 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 16 |
Correct |
1 ms |
596 KB |
Output is correct |
| 17 |
Correct |
1 ms |
724 KB |
Output is correct |
| 18 |
Correct |
1 ms |
596 KB |
Output is correct |
| 19 |
Correct |
1 ms |
724 KB |
Output is correct |
| 20 |
Correct |
1 ms |
592 KB |
Output is correct |
| 21 |
Correct |
117 ms |
2148 KB |
Output is correct |
| 22 |
Correct |
112 ms |
2128 KB |
Output is correct |
| 23 |
Correct |
98 ms |
2128 KB |
Output is correct |
| 24 |
Correct |
146 ms |
2004 KB |
Output is correct |
| 25 |
Correct |
109 ms |
2132 KB |
Output is correct |
| 26 |
Correct |
231 ms |
2044 KB |
Output is correct |
| 27 |
Correct |
268 ms |
2124 KB |
Output is correct |
| 28 |
Correct |
242 ms |
2084 KB |
Output is correct |
| 29 |
Correct |
233 ms |
2020 KB |
Output is correct |
| 30 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 31 |
Correct |
3 ms |
2260 KB |
Output is correct |
| 32 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 33 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 34 |
Correct |
3 ms |
2272 KB |
Output is correct |
| 35 |
Correct |
3 ms |
2260 KB |
Output is correct |
| 36 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 37 |
Correct |
2 ms |
2260 KB |
Output is correct |
| 38 |
Correct |
4 ms |
2260 KB |
Output is correct |
| 39 |
Correct |
2 ms |
724 KB |
Output is correct |
| 40 |
Correct |
2 ms |
724 KB |
Output is correct |
| 41 |
Correct |
2 ms |
724 KB |
Output is correct |
| 42 |
Correct |
2 ms |
724 KB |
Output is correct |
| 43 |
Correct |
2 ms |
724 KB |
Output is correct |
| 44 |
Correct |
4 ms |
716 KB |
Output is correct |
| 45 |
Correct |
3 ms |
724 KB |
Output is correct |
| 46 |
Correct |
3 ms |
724 KB |
Output is correct |
| 47 |
Correct |
3 ms |
724 KB |
Output is correct |
| 48 |
Correct |
4 ms |
724 KB |
Output is correct |
| 49 |
Correct |
2 ms |
732 KB |
Output is correct |
| 50 |
Correct |
2 ms |
716 KB |
Output is correct |
| 51 |
Correct |
2 ms |
724 KB |
Output is correct |
| 52 |
Correct |
2 ms |
724 KB |
Output is correct |
| 53 |
Correct |
2 ms |
724 KB |
Output is correct |
| 54 |
Correct |
1 ms |
468 KB |
Output is correct |
| 55 |
Correct |
1 ms |
468 KB |
Output is correct |
| 56 |
Correct |
2 ms |
468 KB |
Output is correct |
| 57 |
Correct |
1 ms |
468 KB |
Output is correct |
| 58 |
Correct |
1 ms |
468 KB |
Output is correct |
| 59 |
Correct |
128 ms |
2316 KB |
Output is correct |
| 60 |
Correct |
112 ms |
2324 KB |
Output is correct |
| 61 |
Correct |
104 ms |
2312 KB |
Output is correct |
| 62 |
Correct |
148 ms |
2328 KB |
Output is correct |
| 63 |
Correct |
122 ms |
2260 KB |
Output is correct |
| 64 |
Correct |
270 ms |
2276 KB |
Output is correct |
| 65 |
Correct |
276 ms |
2288 KB |
Output is correct |
| 66 |
Correct |
300 ms |
2376 KB |
Output is correct |
| 67 |
Correct |
268 ms |
2260 KB |
Output is correct |
| 68 |
Correct |
265 ms |
2272 KB |
Output is correct |
| 69 |
Correct |
131 ms |
2300 KB |
Output is correct |
| 70 |
Correct |
127 ms |
2260 KB |
Output is correct |
| 71 |
Correct |
120 ms |
2260 KB |
Output is correct |
| 72 |
Correct |
142 ms |
2260 KB |
Output is correct |
| 73 |
Correct |
129 ms |
2316 KB |
Output is correct |
| 74 |
Correct |
25 ms |
700 KB |
Output is correct |
| 75 |
Correct |
22 ms |
724 KB |
Output is correct |
| 76 |
Correct |
23 ms |
592 KB |
Output is correct |
| 77 |
Correct |
24 ms |
600 KB |
Output is correct |
| 78 |
Correct |
25 ms |
596 KB |
Output is correct |
