解题思路：dfs

AC代码如下：

#include<stdio.h>
#include<string.h>

int image[20][20],n,m,nex[4][2]={0,1,1,0,0,-1,-1,0},s,cnt,book[20][20];

bool judge(int x,int y)
{
	if(x<1||x>n||y<1||y>m)
		return true;
	return false;
}

void dfs(int x,int y,int sum,int step)
{
	if(sum>s)
		return ;
	if(sum==s)
	{
		if(cnt>step)
			cnt=step;
		return ;
	}
	int i,nx,ny;
	for(i=0;i<4;i++)
	{
		nx=x+nex[i][0];
		ny=y+nex[i][1];
		if(judge(nx,ny) || book[nx][ny])
			continue;
		book[nx][ny]=1;
		dfs(nx,ny,sum+image[nx][ny],step+1);
		book[nx][ny]=0;
	}
	return ;
}

int main()
{
	int i,j;
	scanf("%d%d",&m,&n);
	s=0;
	for(i=1;i<=n;i++)
		for(j=1;j<=m;j++)
		{
			scanf("%d",&image[i][j]);
			s+=image[i][j];
		}
	if(s%2==0)
	{
		cnt=1010;
		memset(book,0,sizeof(book));
		s/=2;
		book[1][1]=1;
		dfs(1,1,image[1][1],1);
		printf("%d\n",cnt);
	}
	else
		printf("0\n");
	return 0;
}