P3834 模板可持久化线段树 1（主席树） 整体二分

Posted 2022-10-03 bxd123

求区间第k大  整体二分模板提

// luogu-judger-enable-o2
#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define repp(i,a,b) for(int i=(a);i>=(b);--i)
#define ll long long
#define see(x) (cerr<<(#x)<<‘=‘<<(x)<<endl)
#define inf 0x3f3f3f3f
#define CLR(A,v)  memset(A,v,sizeof A)
/////////////////////////////////////
const int N=1e6+10;
int n,m,t[N],k,ans[N],cnt,a[N];
void add(int x,int v)for(;x<=N;x+=x&-x)t[x]+=v;
int qsum(int x)int ans=0;for(;x;x-=x&-x)ans+=t[x];return ans;
struct nodeint l,r,k,op,id;s[N],temp1[N],temp2[N];

void cdq(int l,int r,int L,int R)
   
    if(L>R)return ;
    if(l==r)
    
        rep(i,L,R)if(s[i].op==2)ans[s[i].id]=l;
        return ;
    
    int mid=(l+r)>>1,cnt1=0,cnt2=0;
    rep(i,L,R)
    
        if(s[i].op==1)
        
            if(s[i].l<=mid)add(s[i].id,1),temp1[++cnt1]=s[i];
            else temp2[++cnt2]=s[i];
        
        else 
        
            int x=qsum(s[i].r)-qsum(s[i].l-1);
            if(s[i].k<=x)temp1[++cnt1]=s[i];
            else  s[i].k-=x,temp2[++cnt2]=s[i];
        
    
    rep(i,1,cnt1)if(temp1[i].op==1)add(temp1[i].id,-1);
    rep(i,1,cnt1)s[L-1+i]=temp1[i];
    rep(i,1,cnt2)s[L+cnt1-1+i]=temp2[i];
    cdq(l,mid,L,L+cnt1-1);
    cdq(mid+1,r,L+cnt1,R);

int main()

    cin>>n>>m;
    rep(i,1,n)
    cnt++,scanf("%d",&s[cnt].l),s[cnt].r=1,s[cnt].k=0,s[cnt].id=i,s[cnt].op=1;
    rep(i,1,m)
    
        int l,r,k;scanf("%d%d%d",&l,&r,&k);
        s[++cnt]=(node)l,r,k,2,i;
    
    cdq(-inf,inf,1,cnt);
    rep(i,1,n)
    printf("%d\n",ans[i]);
    return 0;

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