foo.cc: In function 'int main()':
foo.cc:66:13: warning: 'y0' may be used uninitialized in this function [-Wmaybe-uninitialized]
             if(dfs(x0,y0,0,idt))
             ^~
foo.cc:66:13: warning: 'x0' may be used uninitialized in this function [-Wmaybe-uninitialized]

自豪的采用jd5进行评测(github.com/masnn/jd5)