~~那也有5分（~~
by Ender_hz @ 2020-10-25 12:35:39
同问，我也只输出-1
by chenkaiwen @ 2020-10-25 14:47:36
把数据下载下来可以正常输出正确答案，但是洛谷上只输出-1
by chenkaiwen @ 2020-10-25 14:48:40
```cpp
#include<bits/stdc++.h>
using namespace std;
int read(){
int ans = 0 , f = 1 ; char ch = getchar() ;
while(ch < '0' || ch > '9' ){ if(ch == '-' ) f = -1 ; ch = getchar() ; }
while(ch >= '0' &&ch <= '9' ) ans = (ans * 10) + ch - '0' , ch = getchar() ;
return ans * f ;
}
int fx1[4]={1,-1,0,0},fx2[4]={0,0,1,-1};
int a[1000][1000];
bool f[1000][1000];
int n,m;
bool IF(int x,int y){
if(x==n&&y==n){
return 1;
}
// cout<<bool(x!=n+1)<<bool(y!=n+1)<<bool(x!=0)<<bool(y!=0)<<bool(!f[x][y])<<endl;
return x!=n+1&&y!=n+1&&x!=0&&y!=0&&!f[x][y];
}
int dfs(int x,int y,int q){
if(x==n&&y==n){
// cout<<"OK"<<endl;
return 0;
}
f[x][y]=1;
int ans=0x7ffffff;
for(int i=0;i<4;i++){
bool PD=IF(x+fx1[i],y+fx2[i]);
// cout<<x+fx1[i]<<" "<<y+fx2[i]<<" "<<f[x+fx1[i]][y+fx2[i]]<<" "<<q<<endl;
if(a[x+fx1[i]][y+fx2[i]]){
// cout<<"A"<<endl;
if(PD){
if(a[x][y]==a[x+fx1[i]][y+fx2[i]])
ans=min(ans,dfs(x+fx1[i],y+fx2[i],0));
else
ans=min(ans,dfs(x+fx1[i],y+fx2[i],0));
}
}else if(q==0){
// cout<<"B"<<endl;
if(PD){
a[x+fx1[i]][y+fx2[i]]=a[x][y];
ans=min(ans,dfs(x+fx1[i],y+fx2[i],1)+2);
a[x+fx1[i]][y+fx2[i]]=((a[x][y]+1)%2)+1;
ans=min(ans,dfs(x+fx1[i],y+fx2[i],1)+3);
a[x+fx1[i]][y+fx2[i]]=0;
}
}
}
// cout<<"ans "<<x<<" "<<y<<" "<<ans<<endl;
return ans;
}
int main(){
cin>>n>>m;
for(int i=0;i<m;i++){
a[read()][read()]=read()+1;
}
int ans=dfs(1,1,0);
cout<<ans<<endl;
return 0;
}
```
by chenkaiwen @ 2020-10-25 14:49:47
$x2 = x + fx[i]$
$y2 = y + fy[i]$
它们不香吗？
by 蒟蒻·巨弱 @ 2020-10-25 14:50:20
by chenkaiwen @ 2020-10-25 14:52:31
@[蒟蒻·巨弱](/user/309896) emmmm,好像没有什么区别吧
by chenkaiwen @ 2020-10-25 14:53:14
@[chenkaiwen](/user/107527) 强迫症(doge)
by 蒟蒻·巨弱 @ 2020-10-25 15:49:09
@[chenkaiwen](/user/107527) 读入不要用 `a[read ()][read ()]=read ()+1`
by 做梦想Peach @ 2020-11-01 14:58:29
@[做梦想Peach](/user/239030) 太感谢了
by chenkaiwen @ 2020-11-01 18:34:47