#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)
const double EPS = 1e-9;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};
void DBG(){cout << "]" << endl;}
template<typename T, typename ...U> void DBG(const T& head, const U... args){ cout << head << "; "; DBG(args...); }
#define dbg(...) cout << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__);
#define chk() cout << "Check at line(" << __LINE__ << ") hit." << endl;
template<class T, unsigned int U>
ostream& operator<<(ostream& out, const array<T, U> &v){out << "["; REP(i, U) out << v[i] << ", "; out << "]"; return out;}
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "["; REP(i, v.size()) out << v[i] << ", "; out << "]"; return out;}
template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int mod = (int)1e9+7;
struct Mint{
int val;
Mint(){ val = 0; }
Mint(long long v){
val = (-mod <= v && v < mod) ? v : v%mod;
if(val < 0) val+= mod;
}
// operators
Mint operator-(){return Mint(-val);}
Mint& operator+=(const Mint& other){ val+=other.val; if(val >= mod) val-=mod; return *this;}
Mint& operator-=(const Mint& other){ val-=other.val; if(val < 0) val+=mod; return *this;}
Mint& operator*=(const Mint& other){ val=((long long)val*other.val)%mod; return *this;}
friend Mint binpow(Mint a, long long p){
Mint res(1);
while(p > 0){
if(p&1) res*=a; a*=a; p>>=1;
}
return res;
}
friend Mint inv(Mint a){ return binpow(a, mod-2); }
Mint& operator/=(const Mint &other){ return (*this)*=inv(other);}
friend Mint operator+(Mint a, const Mint& b){ return a+=b; }
friend Mint operator-(Mint a, const Mint& b){ return a-=b; }
friend Mint operator*(Mint a, const Mint& b){ return a*=b; }
friend Mint operator/(Mint a, const Mint& b){ return a/=b; }
bool operator==(const Mint &other){return val == other.val;}
bool operator!=(const Mint &other){return val != other.val;}
bool operator<(const Mint &other){return val < other.val;}
// io
friend ostream& operator<<(ostream &out, Mint &a){ return out << a.val; }
};
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
const int mx = 50;
vector<vector<Mint>> ncr(mx, vector<Mint>(mx));
ncr[0][0] = Mint(1);
FOR(i, 1, mx, 1){
ncr[i][0] = ncr[i][i] = Mint(1);
FOR(j, 1, i, 1){
ncr[i][j] = (ncr[i - 1][j - 1] + ncr[i - 1][j]);
}
}
int h, w;
cin >> h >> w;
vector<vector<Mint>> dp(w + 1, vector<Mint>(h + 1, Mint(0)));
FOR(i, 0, h + 1, 1){
dp[0][i] = Mint(1);
}
FOR(i, 0, w + 1, 1){
dp[i][0] = Mint(1);
}
FOR(i, 1, w + 1, 1){
FOR(j, 1, h + 1, 1){
dp[i][j] += dp[i - 1][j];
dp[i][j] += Mint(4) * Mint(j) * dp[i - 1][j - 1];
if(j > 1)
dp[i][j] += ncr[j][2] * dp[i - 1][j - 2];
if(i > 1)
dp[i][j] += Mint(j) * Mint(i - 1) * dp[i - 2][j - 1];
}
}
dp[w][h] -= Mint(1);
cout << dp[w][h] << "\n";
return 0;
}
Compilation message
tents.cpp: In function 'Mint binpow(Mint, long long int)':
tents.cpp:78:13: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
78 | if(p&1) res*=a; a*=a; p>>=1;
| ^~
tents.cpp:78:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
78 | if(p&1) res*=a; a*=a; p>>=1;
| ^
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
204 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| 3 |
Correct |
1 ms |
204 KB |
Output is correct |
| 4 |
Runtime error |
1 ms |
460 KB |
Execution killed with signal 11 |
| 5 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
204 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| 3 |
Correct |
1 ms |
204 KB |
Output is correct |
| 4 |
Runtime error |
1 ms |
460 KB |
Execution killed with signal 11 |
| 5 |
Halted |
0 ms |
0 KB |
- |
