双旋Splay求调
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双旋Splay求调
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Chr0n1CleC楼主2022/9/8 13:58
#include<stdio.h>
#define N 100009

struct Splay
{
	int rt, tot, cnt[N], val[N], fa[N], ch[N][2], siz[N];
	inline void updata(int x)
	{
		siz[x] = siz[ch[x][0]] + siz[ch[x][1]] + cnt[x];
	}
	inline bool get(int x)
	{
		return x == ch[fa[x]][1];
	}
	inline void clear(int x)
	{
		cnt[x] = val[x] = fa[x] = ch[x][0] = ch[x][1] = siz[x] = 0;
	}
	inline void rorate(int x)
	{
		int y = fa[x], z = fa[y], f = get(x);
		ch[y][f] = ch[x][!f];
		if (ch[x][!f])
			fa[ch[x][!f]] = y;
		ch[x][!f] = y;
		fa[y] = x;
		fa[x] = z; 
		if (z)
			ch[z][y == ch[z][1]] = x;
		updata(x), updata(y);
	}
	inline void splay(int x, int root = 0)
	{
		while (fa[x] != root)
		{
			if (get(x) == get(fa[x]))//三点共线 
				rorate(fa[x]);//旋转父节点 
			else
				rorate(x);//旋转子节点 
		}
		if (!root)
			rt = x;//如果时旋转到根,那么根就是 x了 
	}
	inline void insert(int x)
	{
		if (!rt)
		{
			rt = ++ tot;
			val[tot] = x;
			cnt[tot] = 1;//构建新点 
			updata(rt);
			return;
		}//树都没有 
		int cur = rt, f = 0;
		while (1)
		{
			if (val[cur] == x)
			{
				cnt[cur] ++;
				updata(cur);
				updata(f);
				splay(cur);
				return;
			}//重复 
			f = cur;
			cur = ch[cur][val[cur] < x];
			if (!cur)
			{
				ch[f][val[f] < x] = ++ tot;//构建关系 
				fa[tot] = f;//构建关系 
				val[tot] = x;
				cnt[tot] = 1;
				updata(tot);
				updata(f);
				splay(tot);//规定操作完都得splay上去
				return;
			}//到了地方了 
		}
	}
	inline int nxt()
	{
		int cur = ch[rt][1];
		if (!cur)
			return cur;
		while (ch[cur][0])//一直跳 
			cur = ch[cur][0];
		splay(cur);
		return cur;
	}
	inline int pre()
	{
		int cur = ch[rt][0];
		if (!cur)
			return cur;
		while (ch[cur][1])
			cur = ch[cur][1];
		splay(cur);
		return cur; 
	}//同理 
	inline int rank(int x)
	{
		int cur = rt, ret = 0;
		while (cur)
		{
			if (x < val[cur])
				cur = ch[cur][0];
			else
			{
				ret += siz[ch[cur][0]];
				if (x == val[cur])
				{
					splay(cur);
					return ret + 1;
				}
				ret += cnt[cur];
				cur = ch[cur][1];
			}
		}
	}//查找x的排名 
	inline void del(int x)
	{
		rank(x);
		if (cnt[rt] > 1)
		{
			cnt[rt] --, siz[rt] --;
			return;
		}
		if (!ch[rt][0] && !ch[rt][1])
		{
			clear(rt);
			rt = 0;
			return;
		}
		if (!ch[rt][0])
		{
			int cur = rt;
			rt = ch[rt][1];
			fa[rt] = 0;
			clear(cur);
			return;
		}
		if (!ch[rt][1])
		{
			int cur = rt;
			rt = ch[rt][0];
			fa[rt] = 0;
			clear(cur);
			return;
		}
		int cur = rt, k = pre();
		fa[ch[cur][1]] = k;
		ch[k][1] = ch[cur][1];
		clear(cur);
		updata(rt);
	}
	inline int xrank(int x)
	{
		int cur = rt;
		while (1)
		{
			if (ch[cur][0] && x <= siz[ch[cur][0]])
				cur = ch[cur][0];
			else
			{
				x -= siz[ch[cur][0]] + cnt[cur];
				if (x <= 0)
				{
					splay(cur);
					return val[cur];
				}
				cur = ch[cur][1];
			}
		}
	}//查找排名为x的数 
}T;

int main()
{
	int n;
	int opt, x;
	scanf("%d", &n);
	while (n --)
	{
		scanf("%d%d", &opt, &x);
		if (opt == 1)
			T.insert(x);
		if (opt == 2)
			T.del(x);
		if (opt == 3)
			printf("%d\n", T.rank(x));
		if (opt == 4)
			printf("%d\n", T.xrank(x));
		if (opt == 5)
			T.insert(x), printf("%d\n", T.val[T.pre()]), T.del(x);
		if (opt == 6)
			T.insert(x), printf("%d\n", T.val[T.nxt()]), T.del(x);
	}
	
	return 0;
}
2022/9/8 13:58
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