View Compilation Error

0_0_36391439_23992.cpp: In function 'int main()':
0_0_36391439_23992.cpp:164:38: error: 'sort' was not declared in this scope
         sort(nums.begin(), nums.end());
                                      ^
0_0_36391439_23992.cpp:165:51: error: 'unique' was not declared in this scope
         nums.erase(unique(nums.begin(), nums.end()), nums.end());
                                                   ^