View Compilation Error

0_0_24163145_3027.cpp: In function 'void init()':
0_0_24163145_3027.cpp:27:28: error: 'memset' was not declared in this scope
     memset(p,0xff,sizeof(p));
                            ^
0_0_24163145_3027.cpp: In function 'void spfa(int)':
0_0_24163145_3027.cpp:40:35: error: 'memset' was not declared in this scope
     memset(used,false,sizeof(used));
                                   ^