Submission #164182

#	Time	Username	Problem	Language	Result	Execution time	Memory
164182		mhy908	Tents (JOI18_tents)	C++14	100 / 100	162 ms	91132 KiB

tents

#include <bits/stdc++.h>
typedef long long LL;
const LL mod=1000000007;
int n, m;
LL dp[5010][5010];
int main()
{
    scanf("%d %d", &n, &m);
    for(int i=0; i<=5000; i++){
        dp[i][0]=1;
        dp[0][i]=1;
    }
    for(int i=1; i<=n; i++){
		for(int j=1; j<=m; j++){
			dp[i][j]=(dp[i-1][j]+4*j*dp[i-1][j-1])%mod;
			if(i>=2)dp[i][j]=(dp[i][j]+(LL)(i-1)*j*dp[i-2][j-1])%mod;
			if(j>=2)dp[i][j]=(dp[i][j]+(LL)j*(j-1)/2*dp[i-1][j-2])%mod;
		}
	}
    printf("%lld", (dp[n][m]+mod-1)%mod);
}

Compilation message (stderr)

tents.cpp: In function 'int main()':
tents.cpp:8:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~~

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