View Compilation Error

0_0_16311318_28406.cpp: In function 'int main()':
0_0_16311318_28406.cpp:49:29: error: 'memset' was not declared in this scope
  memset(list,-1,sizeof(list));memset(a,0,sizeof(a));memset(dis,0,sizeof(dis));memset(gap,0,sizeof(gap));
                             ^