【贪心】Codeforces Round #402 (Div. 2) C. Dishonest Sellers

#include<cstdio>
#include<algorithm>
using namespace std;
struct Point
{
	int x,y;
}a[200010];
int n,K,ans;
bool cmp(const Point &a,const Point &b)
{
	return a.y-a.x>b.y-b.x;
}
int main()
{
//	freopen("c.in","r",stdin);
	scanf("%d%d",&n,&K);
	for(int i=1;i<=n;++i)
	  scanf("%d",&a[i].x);
	for(int i=1;i<=n;++i)
	  scanf("%d",&a[i].y);
	sort(a+1,a+n+1,cmp);
	int i;
	for(i=1;i<=n;++i)
	  {
	  	if(i>K && a[i].y-a[i].x<0)
	  	  break;
	  	ans+=a[i].x;
	  }
	for(;i<=n;++i)
	  ans+=a[i].y;
	printf("%d\n",ans);
	return 0;
}