P2617 Dynamic Rankings

题目

P2617 Dynamic Rankings

做法

单点修改主席树

纯粹按模板题的做法，建完主席树后修改一个点后面所有的树都得修改\(O(mnlogn)\)，T飞了

树状数组套主席树，在主席树根结点上用树状数组跳着修改O(mlogn^2)

My complete code

// luogu-judger-enable-o2
#include<cstdio>
#include<algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <cctype>
using namespace std;
typedef long long LL;
const LL maxn=1e5+10;
struct node{
    LL l,r,k,val,now;
}q[maxn];
LL n,m,num,num1,num2,cnt; 
LL b[maxn<<1],a[maxn],lt[maxn<<7],rt[maxn<<7],date[maxn<<7],root[maxn],que1[maxn],que2[maxn];
inline LL read(){
    char c; LL f=1;
    c=getchar();
    while(c<'0'||c>'9'){
        if(c=='-')
            f=-1;
        c=getchar();
    }
    LL x=0;
    while(c>='0'&&c<='9'){
        x=x*10+c-'0';
        c=getchar();
    }
    return x*f;
}
inline LL lowbit(LL x){
    return x&-x;
}
inline void update(LL x,LL l,LL r,LL c,LL val){
    while(true){
    	LL mid=(l+r)>>1;
    	date[x]+=val;
    	if(l==r)
    	    return;
    	if(c<=mid){
    	    if(!lt[x]) lt[x]=++num;
            x=lt[x],r=mid;
        }else{
            if(!rt[x]) rt[x]=++num;
            x=rt[x],l=mid+1;
        }
    }
}
inline void add(LL x,LL v){
    LL now=std::lower_bound(b+1,b+1+cnt,a[x])-b;
    for(LL i=x;i<=n;i+=lowbit(i)){
    	if(!root[i])
    	    root[i]=++num;
        update(root[i],1,cnt,now,v);
    }
}
inline LL query(LL l,LL r,LL k){
    while(l!=r){
    	LL sum=0,mid=(l+r)>>1;
        for(LL i=1;i<=num1;++i)
            sum+=date[lt[que1[i]]];
        for(LL i=1;i<=num2;++i)
            sum-=date[lt[que2[i]]];
        if(sum>=k){
            for(LL i=1;i<=num1;++i)
                que1[i]=lt[que1[i]];
            for(LL i=1;i<=num2;++i)
                que2[i]=lt[que2[i]];
            r=mid;
        }else{
            for(LL i=1;i<=num1;++i)
                que1[i]=rt[que1[i]];
            for(LL i=1;i<=num2;++i)
                que2[i]=rt[que2[i]];
            return query(mid+1,r,k-sum);
            l=mid+1,k-=sum;
        }
    }
    return l;
}
int main(){
    n=read(),m=read();
    for(LL i=1;i<=n;++i)
        a[i]=b[++cnt]=read();
    for(LL i=m;i>=1;--i){
        char s[100];
        scanf(" %s",s);
        if(s[0]=='Q')
        	q[i].l=read(),q[i].r=read(),q[i].k=read();
        else
            q[i].k=0,
            q[i].now=read(),q[i].val=read(),
            b[++cnt]=q[i].val;
    }
    std::sort(b+1,b+cnt+1);
    cnt=std::unique(b+1,b+1+cnt)-b-1;
    for(LL i=1;i<=n;++i)
        add(i,1);
    while(m){
        if(q[m].k){
            num1=num2=0;
            for(LL j=q[m].r;j;j-=lowbit(j))
                que1[++num1]=root[j];
            for(LL j=q[m].l-1;j;j-=lowbit(j))
                que2[++num2]=root[j];
            printf("%lld\n",b[query( 1,cnt,q[m].k )]);
        }else{
            add(q[m].now,-1),
            a[q[m].now]=q[m].val,
            add(q[m].now,1);
        }
        --m;
    }
    return 0;
}