#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#ifdef DEBUG
#include <time.h>
#endif
#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x) \
{ \
++recur_depth; \
auto x_ = x; \
--recur_depth; \
cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":" \
<< __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl; \
}
#else
#define dbg(x)
#endif
using namespace std;
using namespace __gnu_pbds;
typedef pair<int, int> ii;
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;
typedef vector<bool> vb;
template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
tree_order_statistics_node_update>;
template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
!is_same<T_container, string>::value,
typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
os << '{';
string sep;
for (const T &x : v)
os << sep << x, sep = ", ";
return os << '}';
}
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e9;
const ld EPS = 1e-9;
void solve() {
int n, m;
cin >> n >> m;
if (n > m)
swap(n, m);
vector<vvl> dp(n + 1, vvl(m + 1, vl(m + 1, -1)));
function<ll(ll, ll, ll)> f = [&](ll r, ll no_free, ll no_put_north) -> ll {
if (r < 0)
return 1;
if (r >= n || no_free < 0 || no_free > m || no_put_north < 0 ||
no_put_north >= m)
return 0;
ll &x = dp[r][no_free][no_put_north];
if (x != -1)
return x;
x = f(r - 1, no_free, no_put_north);
x += f(r - 1, no_free - 2, no_put_north) * (no_free * (no_free - 1)) / 2;
x %= MOD;
x += f(r - 1, no_free, no_put_north - 1) * no_put_north;
x %= MOD;
x += f(r - 1, no_free - 1, no_put_north) * no_free * 3;
x %= MOD;
x += f(r - 1, no_free - 1, no_put_north + 1) * no_free;
x %= MOD;
// cerr << "R: " << r << " NF: " << no_free << " NPN: " << no_put_north
// << "\n";
// cerr << "\t" << x << "\n";
return x;
};
cout << (f(n - 1, m, 0) - 1 + MOD) % MOD << "\n";
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(NULL);
clock_t start = clock();
int test_cases = 1;
// cin >> test_cases;
while (test_cases--)
solve();
#ifdef DEBUG
cerr << fixed << setprecision(10)
<< "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
<< "s\n";
#endif
return 0;
}
Compilation message
tents.cpp: In function 'int main()':
tents.cpp:135:11: warning: unused variable 'start' [-Wunused-variable]
135 | clock_t start = clock();
| ^~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
1364 KB |
Output is correct |
3 |
Correct |
0 ms |
340 KB |
Output is correct |
4 |
Correct |
1 ms |
1620 KB |
Output is correct |
5 |
Correct |
20 ms |
33408 KB |
Output is correct |
6 |
Correct |
39 ms |
37436 KB |
Output is correct |
7 |
Correct |
28 ms |
36388 KB |
Output is correct |
8 |
Correct |
17 ms |
30708 KB |
Output is correct |
9 |
Correct |
1 ms |
980 KB |
Output is correct |
10 |
Correct |
88 ms |
93720 KB |
Output is correct |
11 |
Correct |
4 ms |
8916 KB |
Output is correct |
12 |
Correct |
473 ms |
217400 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
1364 KB |
Output is correct |
3 |
Correct |
0 ms |
340 KB |
Output is correct |
4 |
Correct |
1 ms |
1620 KB |
Output is correct |
5 |
Correct |
20 ms |
33408 KB |
Output is correct |
6 |
Correct |
39 ms |
37436 KB |
Output is correct |
7 |
Correct |
28 ms |
36388 KB |
Output is correct |
8 |
Correct |
17 ms |
30708 KB |
Output is correct |
9 |
Correct |
1 ms |
980 KB |
Output is correct |
10 |
Correct |
88 ms |
93720 KB |
Output is correct |
11 |
Correct |
4 ms |
8916 KB |
Output is correct |
12 |
Correct |
473 ms |
217400 KB |
Output is correct |
13 |
Correct |
34 ms |
79944 KB |
Output is correct |
14 |
Correct |
64 ms |
166904 KB |
Output is correct |
15 |
Runtime error |
238 ms |
524288 KB |
Execution killed with signal 9 |
16 |
Halted |
0 ms |
0 KB |
- |