#include<bits/stdc++.h>
using namespace std;
#define ii pair <int, int>
#define app push_back
#define all(a) a.begin(), a.end()
#define bp __builtin_popcount
#define ll long long
#define mp make_pair
#define f first
#define s second
#define Time (double)clock()/CLOCKS_PER_SEC
const int N = 1007, MOD = 1000 * 1000 * 1000 + 7;
int fp(int a, int p) {
ll ans = 1, c = a;
for (int i = 0; (1ll << i) <= p; ++i) {
if ((p >> i) & 1) ans = ans * c % MOD;
c = c * c % MOD;
}
return ans;
}
int f[N], inv[N];
int n, l[N], r[N], dp[N][N], mem[N][N], cur[N], lmao[N];
signed main() {
#ifdef HOME
freopen("input.txt", "r", stdin);
#else
ios_base::sync_with_stdio(0); cin.tie(0);
#endif
f[0] = inv[0] = 1;
for (int i = 1; i < N; ++i) {
f[i] = ((ll)f[i - 1] * i) % MOD;
inv[i] = fp(f[i], MOD - 2);
}
for (int i = 0; i < N; ++i)
mem[i][0] = 1;
for (int i = 1; i < N; ++i)
for (int j = 1; j < N; ++j)
mem[i][j] = (mem[i - 1][j] + mem[i - 1][j - 1]) % MOD;
cin >> n;
vector <int> c;
for (int i = 1; i <= n; ++i) {
cin >> l[i] >> r[i];
c.app(l[i]); c.app(r[i] + 1);
}
sort(all(c));
c.resize(unique(all(c)) - c.begin());
dp[0][0] = 1;
for (int i = 0; i + 1 < (int)c.size(); ++i) {
cur[0] = 1;
ll t = 1;
for (int j = 1; j <= n; ++j) {
t = (t * (c[i + 1] - c[i] - j + 1)) % MOD;
cur[j] = t * inv[j] % MOD;
}
for (int mx = 1; mx <= n; ++mx) {
lmao[mx] = 0;
for (int cnt = 1; cnt <= mx; ++cnt)
lmao[mx] = (lmao[mx] + (ll)mem[mx - 1][cnt - 1] * cur[cnt]) % MOD;
}
for (int j = 0; j <= n; ++j) {
dp[i + 1][j] = (dp[i + 1][j] + dp[i][j]) % MOD;
int mx = 0;
for (int k = j + 1; k <= n; ++k) {
if (l[k] <= c[i] && c[i + 1] - 1 <= r[k]) {
++mx;
dp[i + 1][k] = (dp[i + 1][k] + (ll)dp[i][j] * lmao[mx]) % MOD;
}
}
}
}
int ans = 0;
for (int i = 1; i <= n; ++i)
ans += dp[c.size() - 1][i];
cout << ans % MOD << '\n';
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
949 ms |
8440 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
949 ms |
8440 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
17 ms |
5112 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
949 ms |
8440 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |