/in/foo.cc: In function 'int dfs(int)':
/in/foo.cc:18:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc:12:8: warning: array subscript is above array bounds [-Warray-bounds]
  f[v][1]=1;
  ~~~~~~^
/in/foo.cc:15:27: warning: array subscript is above array bounds [-Warray-bounds]
   f[v][0]+=f[tree[v][i]][1];
            ~~~~~~~~~~~~~~~^
/in/foo.cc:16:16: warning: array subscript is above array bounds [-Warray-bounds]
   f[v][1]+=min1(f[tree[v][i]][0],f[tree[v][i]][1]);
            ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:16:50: warning: array subscript is above array bounds [-Warray-bounds]
   f[v][1]+=min1(f[tree[v][i]][0],f[tree[v][i]][1]);
                                                  ^
/in/foo.cc:16:10: warning: array subscript is above array bounds [-Warray-bounds]
   f[v][1]+=min1(f[tree[v][i]][0],f[tree[v][i]][1]);
   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:37:34: warning: array subscript is above array bounds [-Warray-bounds]
  cout<<min1(f[root][0],f[root][1]);
                                  ^