foo.cc: In function 'void dfs(int*, int, int, int)':
foo.cc:17:16: error: reference to 'map' is ambiguous
             if(map[a][i])
                ^~~
foo.cc:7:15: note: candidates are: int map [305][305]
 int son[maxn],map[maxn][maxn];
               ^~~
In file included from /usr/include/c++/7/map:61:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:81,
                 from foo.cc:1:
/usr/include/c++/7/bits/stl_map.h:99:11: note:                 template<class _Key, class _Tp, class _Compare, class _Alloc> class std::map
     class map
           ^~~
foo.cc: In function 'int main()':
foo.cc:37:9: error: reference to 'map' is ambiguous
         map[a][b]=1;
         ^~~
foo.cc:7:15: note: candidates are: int map [305][305]
 int son[maxn],map[maxn][maxn];
               ^~~
In file included from /usr/include/c++/7/map:61:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:81,
                 from foo.cc:1:
/usr/include/c++/7/bits/stl_map.h:99:11: note:                 template<class _Key, class _Tp, class _Compare, class _Alloc> class std::map
     class map
           ^~~

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