/in/foo.cc: In function 'void ss(int, int)':
/in/foo.cc:23:57: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(xx>0&&xx<=m&&yy>0&&yy<=n&&(!vis[xx][yy]||xx==startx&&yy==starty)&&a[xx][yy]!=0)
                                               ~~~~~~~~~~^~~~~~~~~~~~
/in/foo.cc:21:19: warning: iteration 3 invokes undefined behavior [-Waggressive-loop-optimizations]
   int xx=x+di[i][1];
            ~~~~~~~^
/in/foo.cc:19:15: note: within this loop
  for(int i=1;i<=4;i++)
              ~^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:37:6: warning: array subscript is above array bounds [-Warray-bounds]
  di[4][1]=0;
  ~~~~^
/in/foo.cc:41:6: warning: array subscript is above array bounds [-Warray-bounds]
  di[4][2]=-1;
  ~~~~^