Submission #338017

#	Time	Username	Problem	Language	Result	Execution time	Memory
338017		BeanZ	Tents (JOI18_tents)	C++14	100 / 100	413 ms	71404 KiB

tents

// I_Love_LPL
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define endl '\n'
const int N = 3005;
long long mod = 1e9 + 7;
const int lim = 700;
const int lg = 18;
const int base = 311;
const long double eps = 1e-6;
ll dp[N][N];
ll DP(ll h, ll w){
    if (h == 0 || w == 0) return 1;
    if (dp[h][w] != -1) return dp[h][w];
    ll res = 0;
    res = res + w * 4 * DP(h - 1, w - 1);
    res = res + DP(h - 1, w);
    if (h > 1) res = res + (h - 1) * w * DP(h - 2, w - 1);
    if (w > 1) res = res + w * (w - 1) / 2 * DP(h - 1, w - 2);
    res = res % mod;
    return dp[h][w] = res;
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    if (fopen("tests.inp", "r")){
        freopen("test.inp", "r", stdin);
        freopen("test.out", "w", stdout);
    }
    ll h, w;
    cin >> h >> w;
    memset(dp, -1, sizeof(dp));
    cout << (DP(h, w) - 1 + mod) % mod;
}
/*

Out:
*/

Compilation message (stderr)

tents.cpp: In function 'int main()':
tents.cpp:28:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   28 |         freopen("test.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
tents.cpp:29:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   29 |         freopen("test.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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