Submission #3556832

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Source Code Expand

#include<iostream>
#include<cstdio>
using namespace std;
char map[501][501];
int search(int sx,int sy);
int vis[501][501];
int ex,ey,n,m;//终点 
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
int main()
{
//	freopen("yudian.in","r","stdin");
//	freopen("yudian.out","w","stdout");
    int i,j,sx,sy;
    cin>>n>>m;
    for(i=1;i<=n;i++)
	   for(j=1;j<=m;j++)
	    cin>>map[i][j];
		if(map[i][j]=='.') map[i][j]=1;//可走 
		if(map[i][j]=='g') ex=i,ey=j;
		if(map[i][j]=='s') sx=i,sy=j;//起点 
	if(search(sx,sy))
	   cout<<"Yes"<<endl;//
	else cout<<"No"<<endl;	
	return 0;
}

int search(int sx,int sy)
{
	int nx,ny;
	if(sx==ex&&sy==ey)
	  return 1;
	for(int z=1;z<=4;z++)
	   nx=sx+dx[z],ny=sy+dy[z];
	   if(nx<=n&&nx>=0&&ny>=0&&ny<=m&&vis[nx][ny]==1)
	      vis[nx][ny]=false;
	      search(nx,ny);
	      vis[nx][ny]=true;//回溯？ 
	if(vis[nx][ny]==1) return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int search(int, int)’:
./Main.cpp:34:15: warning: iteration 3u invokes undefined behavior [-Waggressive-loop-optimizations]
     nx=sx+dx[z],ny=sy+dy[z];
               ^
./Main.cpp:33:15: note: containing loop
  for(int z=1;z<=4;z++)
               ^

Judge Result