delete pics to save space

2.11922.cpp

@@ -0,0 +1,129 @@
+#include<cstdio>
+#include<algorithm>
+using namespace std;
+struct Node
+{
+	Node *ch[2];
+	int s,v,flip;
+	inline int cmp(int k)
+	{
+		int d=k-ch[0]->s;
+		if(d==1) return -1;
+		return d<=0?0:1;
+	}
+	inline void maintain()
+	{
+		s=ch[0]->s+ch[1]->s+1;
+	}
+	inline void pushdown()
+	{
+		if(!flip) return;
+		flip=0;
+		swap(ch[0],ch[1]);
+		ch[0]->flip=!(ch[0]->flip);
+		ch[1]->flip=!(ch[1]->flip);
+	}
+};
+Node *null=new Node();
+inline void rotate(Node* &o,int d)
+{
+	Node *k=o->ch[d^1];
+	o->ch[d^1]=k->ch[d];
+	k->ch[d]=o;
+	o->maintain();
+	k->maintain();
+	o=k;
+}
+void splay(Node* &o,int k)
+{
+	o->pushdown();
+	int d=o->cmp(k);
+	if(d==1) k-=o->ch[0]->s+1;
+	if(d!=-1)
+	{
+		Node *p=o->ch[d];
+		p->pushdown();
+		int d2=p->cmp(k);
+		int k2=(d2==0?k:k - 1 - p->ch[0]->s );
+		if(d2!=-1)
+		{
+			splay(p->ch[d2],k2);
+			if(d==d2) rotate(o,d^1);
+			else rotate(o->ch[d],d);
+		}
+		rotate(o,d^1);
+	}
+}
+inline Node* merge(Node* left,Node* right)
+{
+	splay(left,left->s);
+	left->ch[1]=right;
+	left->maintain();
+	return left;
+}
+inline void split(Node* o,int k,Node* &left,Node* &right)
+{
+	splay(o,k);
+	left=o;
+	right=o->ch[1];
+	o->ch[1]=null;
+	left->maintain();
+}
+const int maxn=101000;
+struct STree
+{
+	int n;
+	Node seq[maxn];
+	Node *root;
+	Node* build(int sz)
+	{
+		if(sz==0) return null;
+		Node* L=build(sz/2);
+		Node* o=&seq[++n];
+		o->v=n;
+		o->ch[0]=L;
+		o->ch[1]=build(sz-sz/2-1);
+		o->s=o->flip=0;
+		o->maintain();
+		return o;
+	}
+	void init(int sz)
+	{
+		n=0;
+		null->s=0;
+		root=build(sz);
+	}
+};
+bool flag;
+void print(Node* o)
+{
+	if(o!=null)
+	{
+		o->pushdown();
+		print(o->ch[0]);
+		if(flag) printf("%d\n",o->v-1);
+		flag=true;
+		print(o->ch[1]);
+	}
+}
+STree ss;
+int n,m,a,b;
+Node *o,*mid,*left,*right;
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d%d",&n,&m);
+	ss.init(n+1);
+	while(m--)
+	{
+		scanf("%d%d",&a,&b);
+		split(ss.root,a,left,o);
+		split(o,b-a+1,mid,right);
+		mid->flip^=1;
+		ss.root=merge(merge(left,right),mid);
+	}
+	print(ss.root);
+	return 0;
+}