View Compilation Error

0_0_18083456_24884.cpp: In function 'int main()':
0_0_18083456_24884.cpp:92:11: error: 'sort' is not a member of 'std'
           std::sort(a+1, a+n+1, cmp);
           ^
0_0_18083456_24884.cpp:97:11: error: 'reverse' is not a member of 'std'
           std::reverse(b+1, b+n+1); 
           ^