View Compilation Error

0_0_24651882_24558.cpp: In function 'int solve()':
0_0_24651882_24558.cpp:19:5: error: 'set' was not declared in this scope
     set<int> v;  
     ^
0_0_24651882_24558.cpp:19:5: note: suggested alternative:
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/set:61:0,
                 from 0_0_24651882_24558.cpp:8:
GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_set.h:90:11: note:   'std::set'
     class set
           ^
0_0_24651882_24558.cpp:19:9: error: expected primary-expression before 'int'
     set<int> v;  
         ^
0_0_24651882_24558.cpp:20:9: error: expected primary-expression before 'int'
     set<int>::iterator it;  
         ^
0_0_24651882_24558.cpp:29:9: error: 'v' was not declared in this scope
         v.insert(i);  
         ^
0_0_24651882_24558.cpp:34:13: error: 'it' was not declared in this scope
             it=v.upper_bound(s-r);
             ^
0_0_24651882_24558.cpp:34:16: error: 'v' was not declared in this scope
             it=v.upper_bound(s-r);
                ^