Submission #2532263

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Source Code Expand

#include<cstdio>
#include<cstring>
using namespace std;
const int N=3005,mod=1e9+7;
int f[2][N][2],n,m,ans;
inline void inc(int &x,int y)
{
	x+=y; x-=x>=mod?mod:0;
}
int main()
{
	register int i,j,k;
	scanf("%d%d",&n,&m);
	for (i=1;i<=n;++i)
	f[0][i][0]=1; f[0][0][1]=1;
	for (i=0;i<m;++i)
	{
		int now=i&1,nxt=now^1;
		memset(f[nxt],0,sizeof(f[nxt]));
		for (j=0;j<=n;++j)
		for (k=0;k<=1;++k)
		{
			if (j) inc(f[nxt][j-1][k|(j==1)],f[now][j][k]);
			if (j) inc(f[nxt][j][k|(j==1)],f[now][j][k]);
			if (n-j) inc(f[nxt][j+1][k],f[now][j][k]);
			if (n-j) inc(f[nxt][j][k],f[now][j][k]);
		}
	}
	for (i=0;i<=n;++i)
	inc(ans,f[m&1][i][1]);
	printf("%d",ans);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:13:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
                     ^

Judge Result