View Compilation Error

0_0_16211160_17266.cpp: In function 'void init()':
0_0_16211160_17266.cpp:12:28: error: 'memset' was not declared in this scope
     memset(k,'\0',sizeof(k));
                            ^
0_0_16211160_17266.cpp: In function 'int Merge(int, int)':
0_0_16211160_17266.cpp:17:30: error: 'swap' was not declared in this scope
     if(k[b].v>k[a].v)swap(a,b);
                              ^
0_0_16211160_17266.cpp:20:56: error: 'swap' was not declared in this scope
     if(k[k[a].l].dis < k[k[a].r].dis)swap(k[a].r,k[a].l);
                                                        ^
0_0_16211160_17266.cpp: In function 'int main()':
0_0_16211160_17266.cpp:57:24: error: 'scanf' was not declared in this scope
     while(scanf("%d",&n) != -1){
                        ^
0_0_16211160_17266.cpp:67:30: error: 'printf' was not declared in this scope
             printf("%d\n",ans);
                              ^