View Compilation Error

0_0_33628837_28128.cpp: In function 'void init()':
0_0_33628837_28128.cpp:27:38: error: 'memset' was not declared in this scope
     cnt=0;memset(head,-1,sizeof(head));
                                      ^
0_0_33628837_28128.cpp: In function 'int getans()':
0_0_33628837_28128.cpp:42:28: error: 'memset' was not declared in this scope
     memset(mx,-1,sizeof(mx));
                            ^