View Compilation Error

0_0_18250860_18583.cpp: In function 'void spfa()':
0_0_18250860_18583.cpp:22:35: error: 'memset' was not declared in this scope
     memset(mark,false,sizeof(mark));
                                   ^
0_0_18250860_18583.cpp: In function 'void Build()':
0_0_18250860_18583.cpp:69:32: error: 'memset' was not declared in this scope
     memset(head,-1,sizeof(head));
                                ^
0_0_18250860_18583.cpp: In function 'void bfs(int)':
0_0_18250860_18583.cpp:83:34: error: 'memset' was not declared in this scope
     memset(level,-1,sizeof(level));
                                  ^
0_0_18250860_18583.cpp: In function 'int SAP(int, int)':
0_0_18250860_18583.cpp:106:30: error: 'memset' was not declared in this scope
     memset(pre,-1,sizeof(pre));
                              ^