In file included from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\unordered_map:35:0,
                 from foo.cpp:11:
c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\bits\c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support is currently experimental, and must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
 #error This file requires compiler and library support for the \
  ^
foo.cpp:21:1: error: 'unordered_map' does not name a type
 unordered_map <int, int> have;
 ^
foo.cpp:23:1: error: 'unordered_map' does not name a type
 unordered_map <int, int> reduce;
 ^
foo.cpp: In function 'void solve()':
foo.cpp:34:2: error: 'have' was not declared in this scope
  have.clear();
  ^
foo.cpp:58:2: error: 'reduce' was not declared in this scope
  reduce.clear();
  ^
foo.cpp:59:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < numbers.size(); i++)
                                  ^
foo.cpp:87:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0; i < e[s].size(); i++)
                                ^