View Compilation Error

0_0_22058813_21962.cpp: In function 'void init()':
0_0_22058813_21962.cpp:20:32: error: 'memset' was not declared in this scope
     memset(head,-1,sizeof(head));
                                ^
0_0_22058813_21962.cpp: In function 'int sap(int, int, int)':
0_0_22058813_21962.cpp:34:31: error: 'memset' was not declared in this scope
     memset(gap, 0, sizeof(gap));
                               ^