bzoj1901:Zju2112 Dynamic Rankings

传送门

权值线段树套区间线段树的裸题，加了离散化就好了
或者也可以整体二分
代码（树套树）：

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<map>
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;
}
#define rg register
const int maxn=1e5+10;
int n,m,id,nmp[maxn*2],x[maxn],y[maxn],z[maxn],num,a[maxn],b[maxn*2],ls[maxn*20],rs[maxn*20],sum[maxn*20],rt[maxn*4];char op[maxn][3];
struct segment_tree
{
	void update(int x){sum[x]=sum[ls[x]]+sum[rs[x]];}
	void change(int &k,int l,int r,int a,int b)
	{
		if(!k)k=++id;int mid=(l+r)>>1;
		if(l==r){sum[k]+=b;return ;}
		if(a<=mid)change(ls[k],l,mid,a,b);
		else change(rs[k],mid+1,r,a,b);
		update(k);
	}
	int get(int x,int l,int r,int a,int b)
	{
		if(!x)return 0;int mid=(l+r)>>1,ans=0;
		if(a<=l&&b>=r)return sum[x];
		if(a<=mid)ans+=get(ls[x],l,mid,a,b);
		if(b>mid)ans+=get(rs[x],mid+1,r,a,b);
		return ans;
	}
}s[maxn*4];
map<int,int>mp;
void change(int x,int l,int r,int a,int b,int c)
{
	s[x].change(rt[x],1,n,a,c);
	if(l==r)return ;int mid=(l+r)>>1;
	if(b<=mid)change(x<<1,l,mid,a,b,c);
	else change(x<<1|1,mid+1,r,a,b,c);
}
int get(int x,int l,int r,int a,int b,int c)
{
	if(l==r)return l;int mid=(l+r)>>1,now=s[x<<1].get(rt[x<<1],1,n,a,b);
	if(c<=now)return get(x<<1,l,mid,a,b,c);
	else return get(x<<1|1,mid+1,r,a,b,c-now);
}
int main()
{
	read(n),read(m);num=n;
	for(rg int i=1;i<=n;i++)read(a[i]),b[i]=a[i];
	for(rg int i=1;i<=m;i++)
	{
		scanf("%s",op[i]+1),read(x[i]),read(y[i]);
		if(op[i][1]=='Q')read(z[i]);
		else b[++num]=y[i];
	}
	sort(b+1,b+num+1);int tot=0;
	for(rg int i=1;i<=num;i++)if(b[i]!=b[i-1])mp[b[i]]=++tot,nmp[tot]=b[i];
	for(rg int i=1;i<=n;i++)change(1,0,num,i,mp[a[i]],1);
	for(rg int i=1;i<=m;i++)
	{
		if(op[i][1]=='C')
		{
			change(1,0,num,x[i],mp[a[x[i]]],-1);
			a[x[i]]=y[i];
			change(1,0,num,x[i],mp[a[x[i]]],1);
		}
		else printf("%d\n",nmp[get(1,0,num,x[i],y[i],z[i])]);
	}
}