answer.code: In function ‘int spfa()’:
answer.code:22:9: error: ‘memset’ was not declared in this scope
   22 |         memset(dis,-1,sizeof(dis));
      |         ^~~~~~
answer.code:3:1: note: ‘memset’ is defined in header ‘<cstring>’; did you forget to ‘#include <cstring>’?
    2 | #include<queue>
  +++ |+#include <cstring>
    3 | using namespace std;
answer.code: In function ‘int main()’:
answer.code:59:17: error: ‘memset’ was not declared in this scope
   59 |                 memset(head,-1,sizeof(head));
      |                 ^~~~~~
answer.code:59:17: note: ‘memset’ is defined in header ‘<cstring>’; did you forget to ‘#include <cstring>’?