0_0_23188569_22500.cpp: In function 'void spfa()': 0_0_23188569_22500.cpp:21:9: error: 'dis' was not declared in this scope mem(dis,inf); ^ 0_0_23188569_22500.cpp:8:26: note: in definition of macro 'mem' #define mem(a,b) memset(a,b,sizeof(a)) ^