Submission #1034073

#	Time	Username	Problem	Language	Result	Execution time	Memory
1034073		vjudge1	Tents (JOI18_tents)	C++14	100 / 100	58 ms	82984 KiB

tents

#include <bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define ull unsigned long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define taskname ""
using namespace std;
const int mod=1e9+7;
ll n,m,i,j,dp[5009][5009];
int main() {
	if (fopen(taskname".inp","r")) {
		freopen(taskname".inp","r",stdin);
		freopen(taskname".out","w",stdout);
	}
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
    cin>>n>>m;
    dp[0][0]=1;
    for(i=1;i<=m;i++)
        dp[0][i]=1;
    for(i=1;i<=n;i++)
    for(j=0;j<=m;j++){
        //TH1:
        dp[i][j]=dp[i-1][j];
        //TH2:
        if(j>=2) dp[i][j]+=dp[i-1][j-2]*j*(j-1)/2;
        //TH3:
        dp[i][j]+=dp[i-1][j-1]*j*4;
        if(i>=2) dp[i][j]+=dp[i-2][j-1]*j*(i-1);
        dp[i][j]%=mod;
    }cout<<(dp[n][m]+mod-1)%mod;
	return 0;
}

Compilation message (stderr)

tents.cpp: In function 'int main()':
tents.cpp:15:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |   freopen(taskname".inp","r",stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
tents.cpp:16:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |   freopen(taskname".out","w",stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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