View Compilation Error

0_0_37725533_5234.cpp: In function 'void Sol()':
0_0_37725533_5234.cpp:147:30: error: 'memset' was not declared in this scope
  memset(tree, 0, sizeof(tree));
                              ^
0_0_37725533_5234.cpp:182:34: error: 'sort' was not declared in this scope
  sort(vec.begin(), vec.end(), cmp);
                                  ^