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https://blog.csdn.net/WilliamSun0122/article/details/77885781
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#include <bits/stdc++.h>
using namespace std;
const int maxn = 6e4+5;
const int maxm = 1e4+5;
int T[maxn],S[maxn],L[maxn*32],R[maxn*32],sum[maxn*32];
int sz[maxn],h[maxn];
int ul[maxn],ur[maxn];
int tot,num,n,q;
struct node{
int l,r,k;
bool flag; //ture代表Q,false代表C
}Q[maxm]; //存储询问
void build(int& rt,int l,int r)
{
rt = ++tot;
sum[rt]=0;
if(l==r) return;
int mid = (l+r)>>1;
build(L[rt],l,mid);
build(R[rt],mid+1,r);
}
void update(int& rt,int pre,int l,int r,int x,int val)
{
rt = ++tot;
L[rt] = L[pre];
R[rt] = R[pre];
sum[rt] = sum[pre]+val;
if(l==r) return;
int mid = (l+r)>>1;
if(x<=mid) update(L[rt],L[pre],l,mid,x,val);
else update(R[rt],R[pre],mid+1,r,x,val);
}
int lowbit(int x)
{
return x&(-x);
}
void add(int x,int val)
{
int res = lower_bound(h+1,h+1+num,sz[x])-h;
while(x<=n)
{
update(S[x],S[x],1,num,res,val);
x += lowbit(x);
}
}
int Sum(int x,bool flag)
{
int res=0;
while(x>0)
{
if(flag) res += sum[L[ur[x]]];
else res += sum[L[ul[x]]];
x -= lowbit(x);
}
return res;
}
int query(int s,int e,int ts,int te,int l,int r,int k)
{
if(l==r) return l;
int mid = (l+r)>>1;
int res = Sum(e,true)-Sum(s,false)+sum[L[te]]-sum[L[ts]];
if(k<=res)
{
for(int i=e;i;i-=lowbit(i)) ur[i] = L[ur[i]];
for(int i=s;i;i-=lowbit(i)) ul[i] = L[ul[i]];
return query(s,e,L[ts],L[te],l,mid,k);
}
else
{
for(int i=e;i;i-=lowbit(i)) ur[i] = R[ur[i]];
for(int i=s;i;i-=lowbit(i)) ul[i] = R[ul[i]];
return query(s,e,R[ts],R[te],mid+1,r,k-res);
}
}
int main()
{
int t;
scanf("%d",&t);
while(t--)
{
char str[5];
num=0;
scanf("%d%d",&n,&q);
for(int i=1;i<=n;i++) scanf("%d",sz+i),h[++num]=sz[i];
for(int i=1;i<=q;i++)
{
scanf("%s",str);
if(str[0]=='Q')
{
scanf("%d%d%d",&Q[i].l,&Q[i].r,&Q[i].k);
Q[i].flag=true;
}
else
{
scanf("%d%d",&Q[i].l,&Q[i].r);
Q[i].flag=false;
h[++num]=Q[i].r;
}
}
sort(h+1,h+1+num);
int tmp = unique(h+1,h+1+num)-h-1;
num = tmp;
tot=0;
build(T[0],1,num);
for(int i=1;i<=n;i++) update(T[i],T[i-1],1,num,lower_bound(h+1,h+1+num,sz[i])-h,1);
for(int i=1;i<=n;i++) S[i] = T[0];
for(int i=1;i<=q;i++)
{
if(Q[i].flag)
{
for(int j=Q[i].r;j;j-=lowbit(j)) ur[j] = S[j];
for(int j=Q[i].l-1;j;j-=lowbit(j)) ul[j] = S[j];
printf("%d\n",h[query(Q[i].l-1,Q[i].r,T[Q[i].l-1],T[Q[i].r],1,num,Q[i].k)]);
}
else
{
add(Q[i].l,-1);
sz[Q[i].l] = Q[i].r;
add(Q[i].l,1);
}
}
}
return 0;
}