Submission #551416

#	Time	Username	Problem	Language	Result	Execution time	Memory
551416		Soul234	Tents (JOI18_tents)	C++14	100 / 100	239 ms	71312 KiB

tents

#include<bits/stdc++.h>
using namespace std;

void DBG() { cerr << "]\n"; }
template<class H, class... T> void DBG(H h, T... t) {
    cerr << h; if(sizeof...(t)) cerr << ", ";
    DBG(t...);
}
#ifdef LOCAL
#define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define dbg(...) 0
#endif // LOCAL

#define FOR(i,a,b) for(int i = (a) ; i<(b) ; i++)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for(int i = (b)-1 ; i>=(a) ; i--)
#define R0F(i,a) ROF(i,0,a)
#define each(e,a) for(auto &e : (a))
#define sz(v) (int)(v).size()
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define pb push_back
#define tcT template<class T
#define nl "\n"

using ll = long long;
using vi = vector<int>;
using pi = pair<int,int>;
using str = string;
tcT> using V = vector<T>;
tcT> using pqg = priority_queue<T,vector<T>,greater<T>>;

void setIO(string NAME = "") {
    cin.tie(0)->sync_with_stdio(0);
    if(sz(NAME)) {
        freopen((NAME + ".inp").c_str(),"r",stdin);
        freopen((NAME + ".out").c_str(),"w",stdout);
    }
}

const int MOD = 1e9 + 7;
const int MX = 3005;

ll dp[MX][MX];
int H, W;

int add(int a, int b) {
    if((a += b) >= MOD) a-=MOD;
    return a;
}

ll mul(ll a, ll b) {
    return 1LL*a*b%MOD;
}

ll calc(int h, int w) {
    if(h <= 0 || w <= 0) return 1;
    if(~dp[h][w]) return dp[h][w];
    ll &res = dp[h][w];
    res = 0;
    res = add(res, calc(h-1, w));
    res = add(res, mul(4, mul(w, calc(h-1, w-1))));
    res = add(res, mul(1LL*w*(w-1)/2, calc(h-1, w-2)));
    res = add(res, mul(1LL*w*(h-1), calc(h-2, w-1)));
    return res;
}

void solve() {
    memset(dp, -1, sizeof dp);
    cin>>H>>W;
    cout << add(calc(H, W), MOD-1) << nl;
}

int main() {
    setIO();

    int t=1;
    //cin>>t;
    while(t-->0) {
        solve();
    }

    return 0;
}

Compilation message (stderr)

tents.cpp: In function 'void setIO(std::string)':
tents.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen((NAME + ".inp").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tents.cpp:38:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |         freopen((NAME + ".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 48 / 48
• Subtask 2: 52 / 52