View Compilation Error

0_0_20995673_13902.cpp: In function 'void solve()':
0_0_20995673_13902.cpp:156:53: error: reference to 'hash' is ambiguous
  For ( i , 1 , n ) insert ( root[i - 1] , root[i] , hash ( p[i].a ) , p[i].s , 1 , cnt ) ;
                                                     ^
0_0_20995673_13902.cpp:50:5: note: candidates are: int hash(int, int, int)
 int hash ( int x , int l = 1 , int r = cnt ) {
     ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/basic_string.h:3068:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/string:52,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/random:40,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_algo.h:66,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/algorithm:62,
                 from 0_0_20995673_13902.cpp:3:
GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^