delete pics to save space

8.1150.cpp

@@ -0,0 +1,69 @@
+#include<cassert>
+#include<cstdio>
+#include<cstring>
+#include<algorithm>
+#include<queue>
+using namespace std;
+const int maxn=100005;
+int N,K,a[maxn],d[maxn];
+struct Node { int val,flg; Node *pre,*nxt; };
+Node mem[maxn],*mcnt=mem,*head,*tail;
+struct DT { int val; Node *from; };
+inline bool operator<(const DT &a,const DT &b) { return a.val>b.val; }
+priority_queue<DT> Q;
+inline Node* insert(int v,Node *p) // insert v after p and return v
+{
+	Node *q=mcnt++;
+	Q.push((DT){v,q});
+	q->val=v; q->flg=1;
+	p->nxt->pre=q;
+	q->nxt=p->nxt;
+	p->nxt=q;
+	q->pre=p;
+	return q;
+}
+void remove(Node *p)
+{
+	if(p==head||p==tail) return;
+	p->pre->nxt=p->nxt;
+	p->nxt->pre=p->pre;
+	p->flg=0;
+}
+void print()
+{
+	Node *p=head->nxt;
+	printf("d:");
+	while(p!=tail) { printf(" %d",p->val); p=p->nxt; }
+	puts("");
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d%d",&N,&K);
+	for(int i=0;i<N;i++) scanf("%d",&a[i]);
+	for(int i=0;i<N-1;i++) d[i]=a[i+1]-a[i];
+	head=mcnt++; tail=mcnt++;
+	head->nxt=tail; tail->pre=head;
+	Node *p=head;
+	for(int i=0;i<N-1;i++) p=insert(d[i],p);
+//	print();
+	int res=0;
+	for(int i=0;i<K;i++)
+	{
+		DT u;
+		while(u=Q.top(),Q.pop(),u.from->flg==0);
+		assert(u.from->flg); assert(u.val==u.from->val);
+		res+=u.val;
+		p=u.from;
+		int t=p->pre->val + p->nxt->val - p->val,hav=(p->pre!=head&&p->nxt!=tail);
+		remove(p->pre); remove(p->nxt);
+		if(hav) { p->val=t; Q.push((DT){t,p}); }
+		else remove(p);
+//		printf("i=%d choose %d\n",i,u.val); print();
+	}
+	printf("%d\n",res);
+	return 0;
+}
+//537092323