//#include <udacha>
#include <iostream>
#include <string>
#include <deque>
#include <vector>
#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <queue>
#include <fstream>
#include <stack>
#include <cmath>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
#include <random>
#include <array>
#include <chrono>
#include <functional>
#include <numeric>
#include <complex>
using namespace std;
#define ll long long
#define ld long double
#define ull uint64_t
#define pll pair<ll, ll>
#define pii pair<int, int>
#define pli pair<ll, int>
#define plli pair<pll, int>
#define pld pair<ld, ld>
#define fst first
#define snd second
#define pdi pair<ld, int>
#define pdd pair<double, double>
#define piii pair<int, pii>
#define forn(i, n) for (int i = 1; i <= n; i++)
#define dforn(i, a, b) for (int i = a; i <= b; i++)
#define rforn(i, n) for (int i = n; i >= 1; i--)
#define rdforn(i, a, b) for (int i = b; i >= a; i--)
#define sforn(i, a, b, s) for (ll i = a; i <= b; i += s)
#define aforn(v, a) for (auto& v : a)
#define sz(a) ((int)a.size())
const int mod = 1e9 + 7;
const ld pi = acos(-1);
const ll N = 2e5 + 1;
const ll inf = 3e18;
const int iinf = 1e9;
const ld dinf = 1e16;
const double eps = 1e-9;
void solve() {
int n, s, f;
cin >> n >> s >> f;
vector<ll> dp(n + 1); dp[0] = 1;
forn(i, n) {
vector<ll> ndp(n + 1);
dforn(j, 0, n) {
if (i == s) {
if (j) (ndp[j] += dp[j]) %= mod;
if (j < n) (ndp[j + 1] += dp[j]) %= mod;
}
else if (i == f) {
if (j) (ndp[j] += dp[j]) %= mod;
if (j < n) (ndp[j + 1] += dp[j]) %= mod;
}
else {
if (j > 1) (ndp[j - 1] += dp[j] * (j - 1) % mod) %= mod;
if (j < n) (ndp[j + 1] += dp[j] * max(0, j + 1 - (i > s) - (i > f)) % mod) %= mod;
}
}
dp = ndp;
}
cout << dp[1] << '\n';
}
int main()
{
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int t = 1;
//cin >> t;
while (t--) solve();
return 0;
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Correct |
1 ms |
348 KB |
Output is correct |
| 4 |
Correct |
1 ms |
348 KB |
Output is correct |
| 5 |
Correct |
1 ms |
348 KB |
Output is correct |
| 6 |
Correct |
1 ms |
348 KB |
Output is correct |
| 7 |
Correct |
1 ms |
600 KB |
Output is correct |
| 8 |
Correct |
1 ms |
344 KB |
Output is correct |
| 9 |
Correct |
1 ms |
348 KB |
Output is correct |
| 10 |
Correct |
1 ms |
348 KB |
Output is correct |
| 11 |
Correct |
1 ms |
344 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Correct |
1 ms |
348 KB |
Output is correct |
| 4 |
Correct |
1 ms |
348 KB |
Output is correct |
| 5 |
Correct |
1 ms |
348 KB |
Output is correct |
| 6 |
Correct |
1 ms |
348 KB |
Output is correct |
| 7 |
Correct |
1 ms |
600 KB |
Output is correct |
| 8 |
Correct |
1 ms |
344 KB |
Output is correct |
| 9 |
Correct |
1 ms |
348 KB |
Output is correct |
| 10 |
Correct |
1 ms |
348 KB |
Output is correct |
| 11 |
Correct |
1 ms |
344 KB |
Output is correct |
| 12 |
Correct |
1 ms |
348 KB |
Output is correct |
| 13 |
Correct |
1 ms |
348 KB |
Output is correct |
| 14 |
Correct |
1 ms |
356 KB |
Output is correct |
| 15 |
Correct |
1 ms |
348 KB |
Output is correct |
| 16 |
Correct |
1 ms |
348 KB |
Output is correct |
| 17 |
Correct |
1 ms |
348 KB |
Output is correct |
| 18 |
Correct |
1 ms |
348 KB |
Output is correct |
| 19 |
Correct |
1 ms |
344 KB |
Output is correct |
| 20 |
Correct |
1 ms |
344 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Correct |
1 ms |
348 KB |
Output is correct |
| 4 |
Correct |
1 ms |
348 KB |
Output is correct |
| 5 |
Correct |
1 ms |
348 KB |
Output is correct |
| 6 |
Correct |
1 ms |
348 KB |
Output is correct |
| 7 |
Correct |
1 ms |
600 KB |
Output is correct |
| 8 |
Correct |
1 ms |
344 KB |
Output is correct |
| 9 |
Correct |
1 ms |
348 KB |
Output is correct |
| 10 |
Correct |
1 ms |
348 KB |
Output is correct |
| 11 |
Correct |
1 ms |
344 KB |
Output is correct |
| 12 |
Correct |
1 ms |
348 KB |
Output is correct |
| 13 |
Correct |
1 ms |
348 KB |
Output is correct |
| 14 |
Correct |
1 ms |
356 KB |
Output is correct |
| 15 |
Correct |
1 ms |
348 KB |
Output is correct |
| 16 |
Correct |
1 ms |
348 KB |
Output is correct |
| 17 |
Correct |
1 ms |
348 KB |
Output is correct |
| 18 |
Correct |
1 ms |
348 KB |
Output is correct |
| 19 |
Correct |
1 ms |
344 KB |
Output is correct |
| 20 |
Correct |
1 ms |
344 KB |
Output is correct |
| 21 |
Correct |
4 ms |
348 KB |
Output is correct |
| 22 |
Correct |
5 ms |
348 KB |
Output is correct |
| 23 |
Correct |
5 ms |
348 KB |
Output is correct |
| 24 |
Correct |
29 ms |
620 KB |
Output is correct |
| 25 |
Correct |
31 ms |
348 KB |
Output is correct |
| 26 |
Correct |
27 ms |
348 KB |
Output is correct |
| 27 |
Correct |
31 ms |
348 KB |
Output is correct |
| 28 |
Correct |
16 ms |
344 KB |
Output is correct |
