#include <iostream>
#include <complex>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <numeric>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <cmath>
#include <bitset>
#include <cassert>
#include <queue>
#include <stack>
#include <deque>
#include <random>
using namespace std;
template<typename T1, typename T2> inline void chkmin(T1 &a, T2 b) {if (a > b) a = b;}
template<typename T1, typename T2> inline void chkmax(T1 &a, T2 b) {if (a < b) a = b;}
#define files(FILENAME) read(FILENAME); write(FILENAME)
#define read(FILENAME) freopen((FILENAME + ".in").c_str(), "r", stdin)
#define write(FILENAME) freopen((FILENAME + ".out").c_str(), "w", stdout)
#define all(c) (c).begin(), (c).end()
#define sz(c) (int)(c).size()
#define left left228
#define right right228
#define y1 y1228
#define mp make_pair
#define pb push_back
#define y2 y2228
#define rank rank228
using ll = long long;
using ld = long double;
const string FILENAME = "input";
const int MAXN = 500 + 7;
const int MAXV = 1000228;
const int Mod = 1e9 + 7;
int n;
int dp[MAXN][MAXN];
int f[MAXV], rf[MAXV];
int add(int a, int b) {
return a + b >= Mod ? a + b - Mod : a + b;
}
int mul(int a, int b) {
return 1LL * a * b % Mod;
}
int powm(int a, int b) {
int res = 1;
while (b > 0) {
if (b & 1) {
res = mul(res, a);
}
a = mul(a, a);
b >>= 1;
}
return res;
}
int dv(int a, int b) {
return mul(a, powm(b, Mod - 2));
}
int comb(int n, int k) {
return mul(f[n], mul(rf[k], rf[n - k]));
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
//read(FILENAME);
f[0] = 1;
for (int i = 1; i < MAXV; i++) {
f[i] = mul(f[i - 1], i);
}
rf[MAXV - 1] = dv(1, f[MAXV - 1]);
for (int i = MAXV - 2; i >= 0; i--) {
rf[i] = mul(rf[i + 1], i + 1);
}
cin >> n;
vector<int> vals;
int res = 0;
for (int i = 1; i <= n; i++) {
int l, r;
cin >> l >> r;
vals.pb(l);
vals.pb(r);
res = add(res, r - l + 1);
}
sort(all(vals));
vals.resize(unique(all(vals)) - vals.begin());
vector<pair<int, int>> segments;
for (int i = 0; i + 1 < sz(vals); i++) {
segments.pb(mp(vals[i], vals[i + 1] - 1));
}
segments.back().second++;
vector<int> lens;
for (auto i: segments) {
lens.pb(i.second - i.first + 1);
}
dp[0][0] = 1;
for (int i = 1; i <= sz(lens); i++) {
for (int j = 0; j <= n; j++) {
for (int k = 0; k <= min(j, lens[i - 1]); k++) {
dp[i][j] = add(dp[i][j], mul(dp[i - 1][j - k], comb(lens[i - 1], k)));
}
}
}
for (int i = 2; i <= n; i++) {
res = add(res, dp[sz(lens)][i]);
}
cout << res << '\n';
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
24 ms |
17388 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
24 ms |
17388 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
20 ms |
17364 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
24 ms |
17388 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |