View Compilation Error

0_0_30420577_21435.cpp: In constructor 'Matrix::Matrix()':
0_0_30420577_21435.cpp:10:29: error: 'memset' was not declared in this scope
         memset(a,0,sizeof(a));
                             ^
0_0_30420577_21435.cpp: In function 'll getans(ll)':
0_0_30420577_21435.cpp:69:28: error: 'sort' was not declared in this scope
     sort(v.begin(), v.end());
                            ^