bzoj 1251: 序列终结者 平衡树，fhqtreap

链接

https://www.lydsy.com/JudgeOnline/problem.php?id=1251

思路

好简单的模板题
不过还是wrong了好几发
叶子节点要注意下,不能使用
遇到就不管
写的fhq-treap，OI中常数最大的平衡树，中间还T了一发

代码

#include <iostream>
#include <ctime>
#include <cstdlib>
#include <cstdio>
using namespace std;
const int N=5e5+7;
int read() {
	int x=0,f=1;char s=getchar();
	for(;s>'9'||s<'0';s=getchar()) if(s=='-') f=-1;
	for(;s>='0'&&s<='9';s=getchar()) x=x*10+s-'0';
	return x*f;
}
int n,m;
int ch[N][2],val[N],pri[N],siz[N],ma[N],tag_1[N],tag_2[N];
int max(int a,int b) {
	return a>b?a:b;
}
void work1(int rt) {
	if(!rt) return;
	swap(ch[rt][0],ch[rt][1]);
	tag_1[rt]^=1;
}
void work2(int rt,int k) {
	if(!rt) return;
	val[rt]+=k;
	ma[rt]+=k;
	tag_2[rt]+=k;
}
void pushdown(int rt) {
	if(tag_1[rt]) {
		work1(ch[rt][0]);
		work1(ch[rt][1]);
		tag_1[rt]=0;
	}
	if(tag_2[rt]) {
		work2(ch[rt][0],tag_2[rt]);
		work2(ch[rt][1],tag_2[rt]);
		tag_2[rt]=0;
	}
}
void pushup(int rt) {
	ma[rt]=max(val[rt],max(ma[ch[rt][0]],ma[ch[rt][1]]));
	siz[rt]=siz[ch[rt][0]]+siz[ch[rt][1]]+1;
}
int cnt;
int build(int l,int r) {
	if(l>r) return 0;
	int mid=(l+r)>>1,p=++cnt;
	ma[p]=val[p]=0,pri[p]=rand(),siz[p]=1;
	ch[p][0]=build(l,mid-1);
	ch[p][1]=build(mid+1,r);
	if(!ch[p][0]) ma[ch[p][0]]=-0x3f3f3f3f;
	if(!ch[p][1]) ma[ch[p][1]]=-0x3f3f3f3f;
	pushup(p);
	return p;
}
int merge(int x,int y) {
	pushdown(x),pushdown(y);
	if(!x||!y) return x+y;
	if(pri[x]<pri[y]) {
		ch[x][1]=merge(ch[x][1],y);
		pushup(x);
		return x;
	} else {
		ch[y][0]=merge(x,ch[y][0]);
		pushup(y);
		return y;
	}
}
void split(int now,int &x,int &y,int k) {
	if(!now) x=y=0; 
	else {
		pushdown(now);
		if(siz[ch[now][0]]+1<=k)
			x=now,split(ch[now][1],ch[x][1],y,k-siz[ch[now][0]]-1);
		else 
			y=now,split(ch[now][0],x,ch[y][0],k);
		pushup(now);
	}
}
void debug(int now ){
	pushdown(now);
	if(!now) return;
	debug(ch[now][0]);
	cout<<val[now]<<" ";
	debug(ch[now][1]);
}
int main() {
	n=read(),m=read();
	int rt=build(1,n);
	for(int i=1;i<=m;++i) {
		int opt=read(),l=read(),r=read(),x,y,z;
		if(opt==1) {
			int v=read();
			split(rt,x,z,r);
			split(x,x,y,l-1);
			work2(y,v);
			rt=merge(merge(x,y),z);
		} 
		else if(opt==2) {
			split(rt,x,z,r);
			split(x,x,y,l-1);
			work1(y);
			rt=merge(merge(x,y),z);
		} else {
			split(rt,x,z,r);
			split(x,x,y,l-1);
			printf("%d
",ma[y]);
			rt=merge(merge(x,y),z);
		}
		// debug(rt);puts("");
	}
	return 0;
}
/*
10 3
1 3 9 -5705
2 2 6 
3 7 8
*/