// Template
#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <iomanip>
#include <tuple>
#include <utility>
#include <queue>
#include <set>
#include <map>
#include <array>
#include <cassert>
#include <cmath>
#define rep_override(x, y, z, name, ...) name
#define rep2(i, n) for (int i = 0; i < (int)(n); ++i)
#define rep3(i, l, r) for (int i = (int)(l); i < (int)(r); ++i)
#define rep(...) rep_override(__VA_ARGS__, rep3, rep2)(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
using namespace std;
using ll = long long;
constexpr int inf = 1001001001;
constexpr ll infll = 3003003003003003003LL;
template <typename T>
inline bool chmin(T &x, const T &y) {
if (x > y) {
x = y;
return true;
}
return false;
}
template <typename T>
inline bool chmax(T &x, const T &y) {
if (x < y) {
x = y;
return true;
}
return false;
}
template <typename T>
istream &operator>>(istream &is, vector<T> &vec) {
for (T &element : vec) is >> element;
return is;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &vec) {
for (int i = 0, vec_len = (int)vec.size(); i < vec_len; ++i) {
os << vec[i] << (i + 1 == vec_len ? "" : " ");
}
return os;
}
struct IOSET {
IOSET() {
cin.tie(nullptr);
ios::sync_with_stdio(false);
cout << fixed << setprecision(10);
}
} ioset;
// Mod-Int
#include <iostream>
template <unsigned int mod>
struct ModInt {
static_assert(mod >= 1 && mod < (1u << 31));
unsigned int val;
ModInt() : val(0) {}
ModInt(long long x) : val(x < 0 ? x % mod + mod : (unsigned long long)x % mod) {}
ModInt<mod> &operator+=(const ModInt<mod> &x) {
val += x.val;
if (val >= mod) val -= mod;
return *this;
}
ModInt<mod> &operator-=(const ModInt<mod> &x) {
if (val < x.val) val += mod;
val -= x.val;
return *this;
}
ModInt<mod> &operator*=(const ModInt<mod> &x) {
unsigned long long s = (unsigned long long)val * x.val;
val = (unsigned int)(s % mod);
return *this;
}
ModInt<mod> operator+() const {
return *this;
}
ModInt<mod> operator-() const {
return ModInt<mod>(0u) - *this;
}
friend ModInt<mod> operator+(const ModInt<mod> &x, const ModInt<mod> &y) {
return ModInt<mod>(x) += y;
}
friend ModInt<mod> operator-(const ModInt<mod> &x, const ModInt<mod> &y) {
return ModInt<mod>(x) -= y;
}
friend ModInt<mod> operator*(const ModInt<mod> &x, const ModInt<mod> &y) {
return ModInt<mod>(x) *= y;
}
friend std::istream &operator>>(std::istream &is, ModInt<mod> &x) {
is >> x.val;
// x.value %= mod;
return is;
}
friend std::ostream &operator<<(std::ostream &os, const ModInt<mod> &x) {
os << x.val;
return os;
}
ModInt<mod> pow(unsigned long long x) const {
ModInt<mod> res(1), s(*this);
while (x) {
if (x & 1) res *= s;
s *= s;
x >>= 1;
}
return res;
}
// --- prime number ---
ModInt<mod> &operator/=(const ModInt<mod> &x) {
*this *= x.pow(mod - 2);
return *this;
}
friend ModInt<mod> operator/(const ModInt<mod> &x, const ModInt<mod> &y) {
return ModInt<mod>(x) /= y;
}
};
// Main
int main() {
constexpr unsigned mod = 1000000007;
using Mint = ModInt<mod>;
int n;
cin >> n;
vector<int> a(n), b(n);
rep(i, n) {
cin >> a[i] >> b[i];
++b[i];
}
vector<int> ps;
ps.reserve(2 * n);
rep(i, n) {
ps.push_back(a[i]);
ps.push_back(b[i]);
}
sort(all(ps));
ps.erase(unique(all(ps)), ps.end());
rep(i, n) {
a[i] = lower_bound(all(ps), a[i]) - ps.begin();
b[i] = lower_bound(all(ps), b[i]) - ps.begin();
}
int k = ps.size() - 1;
vector<vector<Mint>> comb(k, vector<Mint>(n + 1));
rep(i, k) {
int d = ps[i + 1] - ps[i];
Mint p(1);
comb[i][0] = Mint(1);
rep(j, 1, min(d, n) + 1) {
p *= Mint(d - j + 1);
p /= Mint(j);
comb[i][j] = p;
}
}
vector<vector<Mint>> comb2(n + 1, vector<Mint>(n + 1));
comb2[0][0] = Mint(1);
rep(i, 1, n + 1) rep(j, i + 1) {
comb2[i][j] += comb2[i - 1][j];
if (j != 0) comb2[i][j] += comb2[i - 1][j - 1];
}
vector<vector<Mint>> _sum(k, vector<Mint>(n + 1));
rep(i, k) {
int d = ps[i + 1] - ps[i];
_sum[i][1] = Mint(d);
rep(j, 2, min(d, n) + 1) {
rep(l, 2, j + 1) {
_sum[i][j] += comb[i][l] * comb2[j][l] - Mint(2) * comb[i - 1][l] * comb2[j][l] + comb[i - 2][l] * comb2[j][l];
}
}
}
vector<vector<Mint>> dp(n + 1, vector<Mint>(k + 1)), sum(n + 1, vector<Mint>(k + 1));
dp[0][0] = Mint(1);
sum[0] = vector<Mint>(k + 1, Mint(1));
rep(i, n) {
dp[i + 1] = dp[i];
sum[i + 1][0] = dp[i + 1][0];
rep(j, 1, k + 1) {
int d = ps[j] - ps[j - 1];
int cnt = 0;
for (int l = i; l >= 0; --l) {
if (b[l] <= j - 1 || a[l] >= j) {
if (l == i) break;
continue;
}
if (++cnt > d) break;
dp[i + 1][j] += _sum[j - 1][cnt] * sum[l][j - 1];
}
sum[i + 1][j] = sum[i + 1][j - 1] + dp[i + 1][j];
}
}
cout << sum[n][k] - Mint(1) << '\n';
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
47 ms |
10504 KB |
Execution killed with signal 11 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
47 ms |
10504 KB |
Execution killed with signal 11 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
5 ms |
844 KB |
Execution killed with signal 11 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
47 ms |
10504 KB |
Execution killed with signal 11 |
| 2 |
Halted |
0 ms |
0 KB |
- |
