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| #include <iostream>
#include <memory.h>
#include <algorithm>
using namespace std;
#define Size 500
int board[Size][Size];
bool visited[Size][Size];
int N, M;
int dx[4] = {0,1,0,-1};
int dy[4] = {-1,0,1,0};
int edx[4][3] = {{-1,0,1}, {1,1,1}, {-1,0,1}, {-1,-1,-1}};
int edy[4][3] = {{-1,-1,-1}, {-1,0,1}, {1,1,1}, {-1,0,1}};
int ans = 0;
void dfs_excp(int x, int y)
{
for(int i=0;i<4;i++)
{
int point = board[y][x];
for(int j=0;j<3;j++)
{
int nx = x + edx[i][j];
int ny = y + edy[i][j];
if(0<=nx && nx<M && 0<=ny && ny<N) {
point += board[ny][nx];
}
else {
point = 0;
}
}
ans = max(ans,point);
}
}
void dfs(int depth, int x, int y, int point)
{
if(depth==4) {
ans = max(ans, point);
return ;
}
visited[y][x] = true;
for(int i=0;i<4;i++)
{
int nx = x+dx[i];
int ny = y+dy[i];
if(0<=nx && nx<M && 0<=ny && ny<N && !visited[ny][nx])
dfs(depth+1,nx,ny,point+board[ny][nx]);
}
visited[y][x] = false;
}
int main(void)
{
memset(visited,false,sizeof(visited));
cin>>N>>M;
for(int i=0;i<N;i++)
for(int j=0;j<M;j++)
cin>>board[i][j];
for(int i=0;i<N;i++)
for(int j=0;j<M;j++)
{
dfs(1,j,i,board[i][j]);
dfs_excp(j,i);
}
cout<<ans<<endl;
}
|
