Submission #555502

#	TimeUTC-0	Username	Problem	Language	Result	Execution time	Memory
555502	2022-05-01 06:05:41	wenqi	Tents (JOI18_tents)	C++17	100 / 100	291 ms	41700 KiB

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// trans rights
#include <bits/extc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
constexpr int mod = 1000000007;
int W, H;
int cache[3069][3069];
bool done[3069][3069];
int dp(int i, int j)
{
    if (i <= 0 or j <= 0)
        return 1;
    bool &d = done[i][j];
    int &ans = cache[i][j];
    if (d)
        return ans;
    ans = (4ll * j * dp(i - 1, j - 1) + dp(i - 1, j)) % mod;
    ll B = ((ll) j * (j - 1)) / 2;
    if (i >= 2)
        ans = (ans + (ll) (i - 1) * j * dp(i - 2, j - 1)) % mod;
    if (j >= 2)
        ans = (ans + B * dp(i - 1, j - 2)) % mod;
    d = true;
    return ans;
 
 
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• Subtask 1: 48 / 48
• Subtask 2: 52 / 52