Submission #1354176

---

Source Code Expand

#include<bits/stdc++.h>
const int p=1e9+7;

void up(int &a,int b){(a+=b)>=p&&(a-=p);}

int f[3001][3002][2],n,m,ans;

int main()
{
    scanf("%d%d",&n,&m),f[0][0][1]=1;
    for(int i=1;i<=n;++i)f[0][i][0]=1;

    for(int i=0;i<m;++i)
    {
	up(f[i+1][1][1],f[i][0][1]);
	up(f[i+1][1][1],f[i][1][0]);
	up(f[i+1][2][0],f[i][1][0]);
	up(f[i+1][1][1],f[i][1][1]);
	up(f[i+1][2][1],f[i][1][1]);
	for(int j=2;j<=n;++j)
	    for(int k=0;k<2;++k)
	    {
		up(f[i+1][j][k],f[i][j][k]);
		up(f[i+1][j+1][k],f[i][j][k]);
	    }

	for(int j=1;j<=n;++j)
	    for(int k=0;k<2;++k)
		up(f[i+1][j-1][k],f[i+1][j][k]);
    }

    for(int i=0;i<=n;++i)up(ans,f[m][i][1]);
    printf("%d\n",ans);
    
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:10:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&m),f[0][0][1]=1;
                                     ^

Judge Result