传送门
暴力啊，直接树套树上啊
线段树套splay，卡卡常就直接A了
代码：
#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;
void read(int &x) {
char ch; bool ok;
for(ok=0,ch=getchar(); !isdigit(ch); ch=getchar()) if(ch=='-') ok=1;
for(x=0; isdigit(ch); x=x*10+ch-'0',ch=getchar()); if(ok) x=-x;
}
void print(int x){
if(x<0)putchar('-'),x=-x;
if(x>9)print(x/10);
putchar(x%10+'0');
}
#define rg register
const int maxn=5e4+10;
int n,m,a[maxn],cnt[maxn*30],size[maxn*30],ch[maxn*30][2],rt[maxn*4],f[maxn*30],id,v[maxn*30],tot;
struct splay_tree
{
void update(int x){size[x]=size[ch[x][0]]+size[ch[x][1]]+cnt[x];}
void move(int &k,int x)
{
int tmp=ch[f[x]][1]==x,fa=f[x],faa=f[fa];
if(k==fa)k=x;
else ch[faa][ch[faa][1]==fa]=x;
ch[fa][tmp]=ch[x][tmp^1];f[ch[x][tmp^1]]=fa;
ch[x][tmp^1]=fa,f[x]=faa,f[fa]=x;
update(fa),update(x);
}
void splay(int &k,int x)
{
while(k!=x)
{
int y=f[x],z=f[y];
if(y!=k)
{
if((ch[y][0]==x)^(ch[z][0]==y))move(k,y);
else move(k,x);
}
move(k,x);
}
}
int get_pre(int k)
{
int now=ch[rt[k]][0];
while(ch[now][1])now=ch[now][1];
return now;
}
void del(int k,int x)
{
splay(rt[k],x);
if(!ch[x][0]&&!ch[x][1]){rt[k]=0;return ;}
else if(!ch[x][0]&&ch[x][1]){rt[k]=ch[x][1],f[rt[k]]=0;return ;}
else if(ch[x][0]&&!ch[x][1]){rt[k]=ch[x][0],f[rt[k]]=0;return ;}
int g=get_pre(k);splay(rt[k],g);
ch[g][1]=ch[x][1],f[ch[x][1]]=g;update(g);
}
void insert(int z,int x,int y)
{
if(!rt[z]){rt[z]=++id,v[rt[z]]=x,size[rt[z]]=cnt[rt[z]]=1;return ;}
int now=rt[z];
while(1)
{
if(x==v[now]){cnt[now]+=y,update(now);if(!cnt[now])del(z,now);else splay(rt[z],now);return ;}
else if(x<v[now])
{
if(!ch[now][0])
{
ch[now][0]=++id,size[id]=cnt[id]=1;
v[id]=x,f[id]=now;
update(now);break;
}
else now=ch[now][0];
}
else
{
if(!ch[now][1])
{
ch[now][1]=++id,size[id]=cnt[id]=1;
v[id]=x,f[id]=now;
update(now);break;
}
else now=ch[now][1];
}
}
splay(rt[z],id);
}
int findmn(int k,int x)
{
if(!k||!x)return 0;
if(v[k]==x)return size[ch[k][0]];
if(v[k]>x)return findmn(ch[k][0],x);
return size[ch[k][0]]+cnt[k]+findmn(ch[k][1],x);
}
int findmx(int k,int x)
{
if(!k||!x)return 0;
if(v[k]==x)return size[ch[k][0]]+cnt[k];
if(v[k]>x)return findmx(ch[k][0],x);
return size[ch[k][0]]+cnt[k]+findmx(ch[k][1],x);
}
int find(int k,int x)
{
if(!k)return 0;
if(x<=size[ch[k][0]])return find(ch[k][0],x);
if(x>size[ch[k][0]]&&x<=size[ch[k][0]]+cnt[k])return v[k];
return find(ch[k][1],x-size[ch[k][0]]-cnt[k]);
}
int pre(int k,int x)
{
int tmp=find(rt[k],findmn(rt[k],x));
return tmp?tmp:-2147483647;
}
int nxt(int k,int x)
{
int tmp=find(rt[k],findmx(rt[k],x)+1);
return tmp?tmp:2147483647;
}
}s[maxn*4];
void change(int x,int l,int r,int a,int b,int c)
{
s[x].insert(x,b,c);
if(l==r)return ;int mid=(l+r)>>1;
if(a<=mid)change(x<<1,l,mid,a,b,c);
else change(x<<1|1,mid+1,r,a,b,c);
}
int query(int x,int l,int r,int a,int b,int c)
{
if(a<=l&&b>=r)return s[x].findmn(rt[x],c);
int mid=(l+r)>>1,ans=0;
if(a<=mid)ans+=query(x<<1,l,mid,a,b,c);
if(b>mid)ans+=query(x<<1|1,mid+1,r,a,b,c);
return ans;
}
int find_pre(int x,int l,int r,int a,int b,int c)
{
if(a<=l&&b>=r){return s[x].pre(x,c);}
int mid=(l+r)>>1,ans=-2147483647;
if(a<=mid)ans=max(ans,find_pre(x<<1,l,mid,a,b,c));
if(b>mid)ans=max(ans,find_pre(x<<1|1,mid+1,r,a,b,c));
return ans;
}
int find_nxt(int x,int l,int r,int a,int b,int c)
{
if(a<=l&&b>=r){return s[x].nxt(x,c);}
int mid=(l+r)>>1,ans=2147483647;
if(a<=mid)ans=min(ans,find_nxt(x<<1,l,mid,a,b,c));
if(b>mid)ans=min(ans,find_nxt(x<<1|1,mid+1,r,a,b,c));
return ans;
}
bool check(int x,int y,int z,int k){return query(1,1,n,y,z,x)+1<=k;}
int main()
{
read(n),read(m);
for(rg int i=1;i<=n;i++)read(a[i]),change(1,1,n,i,a[i],1);
for(rg int i=1,opt,x,y,z;i<=m;i++)
{
read(opt),read(x),read(y);
if(opt==1)read(z),print(query(1,1,n,x,y,z)+1),puts("");
if(opt==2)
{
read(z);int l=0,r=1e8;
while(l<=r)
{
int mid=(l+r)>>1;
if(check(mid,x,y,z))l=mid+1;
else r=mid-1;
}
print(r);puts("");
}
if(opt==3)change(1,1,n,x,a[x],-1),a[x]=y,change(1,1,n,x,a[x],1);
if(opt==4)read(z),print(find_pre(1,1,n,x,y,z)),puts("");
if(opt==5)read(z),print(find_nxt(1,1,n,x,y,z)),puts("");
}
}