Submission #388623

#	Time	Username	Problem	Language	Result	Execution time	Memory
388623		denkendoemeer	Tents (JOI18_tents)	C++14	100 / 100	255 ms	31940 KiB

tents

#include<bits/stdc++.h>
#define mod 1000000007
using namespace std;
#define ll long long
int dp[3005][3005];
ll calc(int a,int b)
{
    if (a<=0 || b<=0)
        return 1;
    if (dp[a][b])
        return dp[a][b];
    ll ans=0;
    ans+=calc(a-1,b);
    ans+=(b*(a-1))*calc(a-2,b-1);
    ans+=((b*(b-1))/2)*calc(a-1,b-2);
    ans+=calc(a-1,b-1)*b*4;
    ans=ans%mod;
    dp[a][b]=ans;
    return ans;
}
int main()
{
    //freopen(".in","r",stdin);
    //freopen(".out","w",stdout);
    int n,m;
    scanf("%d%d",&n,&m);
    printf("%lld\n",calc(n,m)-1);
return 0;
}

Compilation message (stderr)

tents.cpp: In function 'int main()':
tents.cpp:26:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   26 |     scanf("%d%d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~

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