PAT2-11. 两个有序链表序列的合并

#include<iterator>#include<list>#include<cstdio>using namespace std;int main(){  list<int>a,b,c;  int k;  while(scanf("%d",&k),k!=-1)    a.push_back(k);  while(scanf("%d",&k),k!=-1)    b.push_back(k);  auto it1=a.begin(),it2=b.begin();  auto it3=back_inserter(c);    while(it1!=a.end() && it2!=b.end())    *it3++=(*it1<*it2?*it1++:*it2++);  if(it1==a.end())    copy(it2,b.end(),it3);  if(it2==b.end())    copy(it1,a.end(),it3);  for(auto x:c){    static bool first=true;    if(first)first=false;    else putchar(' ');    printf("%d",x);  }  if(c.size()==0)printf("NULL");  return 0;}

两个有序序列的merge