View Compilation Error

0_0_26373246_1587.cpp: In member function 'void Team::init(std::string)':
0_0_26373246_1587.cpp:20:29: error: 'memset' was not declared in this scope
   memset(Dirt,0,sizeof(Dirt));
                             ^
0_0_26373246_1587.cpp: In member function 'void Submit::scan()':
0_0_26373246_1587.cpp:90:20: error: 'strlen' was not declared in this scope
   int len=strlen(st);
                    ^
0_0_26373246_1587.cpp: In member function 'void Submit::work()':
0_0_26373246_1587.cpp:116:67: error: 'sort' was not declared in this scope
     sort(a[id].lastAC+1,a[id].lastAC+a[id].Solved+1,greater<int>());
                                                                   ^
0_0_26373246_1587.cpp: In function 'int main()':
0_0_26373246_1587.cpp:168:17: error: 'sort' was not declared in this scope
   sort(S+1,S+n+1);
                 ^