普通版代码:
//Author:PanDaoxi
#include <iostream>
using namespace std;
int dx[5]={
-1,0,1,0},dy[5]={
0,1,0,-1};
int G[51][51],vis[51][51],n,sx,sy,ex,ey;
bool f=false;
void dfs(int x,int y){
if(x==ex&&y==ey){
cout<<"yes";
f=true;
return;
}
for(int i=0;i<4;i++){
int x2=x+dx[i],y2=y+dy[i];
if(x2>=1&&x2<=n&&y2>=1&&y2<=n&&G[x2][y2]&&!vis[x2][y2]){
vis[x2][y2]=1;
dfs(x2,y2);
}
}
}
int main(){
cin>>n;
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
cin>>G[i][j];
}
}
cin>>sx>>sy>>ex>>ey;
if(sx==ex&&sy==ey){
cout<<"yes";
return 0;
}
vis[sx][sy]=1;
dfs(sx,sy);
if(!f){
cout<<"no";
}
return 0;
}
加强版代码:
//Author:PanDaoxi
#include <iostream>
using namespace std;
int dx[5]={
-1,0,1,0},dy[5]={
0,1,0,-1};
int G[31][31],vis[31][31],n,sx,sy,ex,ey,A[1000][3];
bool f=false;
void dfs(int x,int y,int d){
if(x==ex&&y==ey){
for(int i=0;i<d-1;i++){
cout<<"("<<A[i][0]<<","<<A[i][1]<<")"<<"-->";
}
cout<<"("<<ex<<","<<ey<<")";
f=true;
return;
}
for(int i=0;i<4;i++){
int xx=x+dx[i],yy=y+dy[i];
if(xx>=1&&xx<=n&&yy>=1&&yy<=n&&G[xx][yy]&!vis[xx][yy]){
vis[xx][yy]=1;
A[d][0]=xx,A[d][1]=yy;
dfs(xx,yy,d+1);
}
}
}
int main(){
cin>>n;
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
cin>>G[i][j];
}
}
cin>>sx>>sy>>ex>>ey;
if(sx==ex&&sy==ey){
cout<<"yes"<<endl;
return 0;
}
A[0][0]=sx,A[0][1]=sy;
vis[sx][sy]=1;
dfs(sx,sy,1);
if(!f){
cout<<"no"<<endl;
}
return 0;
}