USACO 木瓜的丛林

#include<iostream>
using namespace std;

int r,c,p[42][42],ans;

void dfs(int x,int y)
{
ans+=p[x][y];
p[x][y]=0;

if(x==r && y==c)
return;

if(p[x-1][y]>p[x+1][y] && p[x-1][y]>p[x][y-1] && p[x-1][y]>p[x][y+1])
dfs(x-1,y);
else if(p[x+1][y]>p[x][y-1] && p[x+1][y]>p[x][y+1])
dfs(x+1,y);
else if(p[x][y-1]>p[x][y+1])
dfs(x,y-1);
else
dfs(x,y+1);

return;
}

void read()
{
int i,j;

std::ios::sync_with_stdio(false);

cin>>r>>c;
for(i=1; i<=r; i++)
for(j=1; j<=c; j++)
cin>>p[i][j];

dfs(1,1);

cout<<ans;

return;
}

int main()
{
read();
return 0;
}