Submission #957876

#	Time	Username	Problem	Language	Result	Execution time	Memory
957876		vjudge1	Abracadabra (CEOI22_abracadabra)	C++17	25 / 100	3050 ms	22860 KiB

Main

#include<stdio.h>
#include<stdlib.h>

#define N 200004
int n,a[N],t[N],q,sz[N],at[N],zz[1000005];

void upd(int p,int k) { for(;p<N;p|=p+1)t[p]+=k; }
int qry(int p) {int z=0;for(;p>0;p&=p-1)z+=t[p-1];return z;}

void add(int p,int k) { sz[p]=k; upd(p,k); }
void rem(int p) { upd(p,-sz[p]); }

int grp(int x)
{
    if(x<=0)return -1;
    int p=0,v=0;
    for(int j=1<<19;j>0;j>>=1) if(p+j<=N&&v+t[p+j-1]<x)p+=j,v+=t[p-1];
    return p;
}

int ii[1000000],tt[1000000],ww[1000087],head[N],link[N],ho;

void shuffle()
{
    static int done=0;
    if(done)return;
    int g1=grp(n/2),g2=grp(n/2+1);
    if(g1!=g2){done=1;return;}
    int rl=qry(g1);
    int st=at[g1];
    int md=n/2-rl+at[g1];
    int ed=at[g1]+sz[g1];
    for(int l=md,j=md;j<=ed;++j) if(j==ed||a[j]>a[l])add(a[l],j-l),l=j;
    rem(g1);
    add(g1,n/2-rl);
}

int main()
{
    scanf("%d%d",&n,&q);
    for(int i=1;i<=n;++i)scanf("%d",a+i),at[a[i]]=i;
    for(int l=1,i=1;i<=n+1;++i) if(i==n+1||a[i]>a[l]) add(a[l],i-l),l=i;

    for(int p,i=0;i<q;++i)
    {
        scanf("%d%d",tt+i,ii+i);
        if(tt[i]>n+1)tt[i]=n+1;
        ww[++ho]=i;
        link[ho]=head[tt[i]];
        head[tt[i]]=ho;
    }

    for(int i=0;i<=n+1;++i)
    {
        for(int j=head[i];j;j=link[j])
        {
            int k=ww[j];
            int gg=grp(ii[k]);
            int idx=ii[k]-qry(gg);
            zz[k]=a[at[gg]+idx-1];
        }
        shuffle();
    }

    for(int i=0;i<q;++i)printf("%d\n",zz[i]);

    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'void shuffle()':
Main.cpp:30:9: warning: unused variable 'st' [-Wunused-variable]
   30 |     int st=at[g1];
      |         ^~
Main.cpp: In function 'int main()':
Main.cpp:44:13: warning: unused variable 'p' [-Wunused-variable]
   44 |     for(int p,i=0;i<q;++i)
      |             ^
Main.cpp:40:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |     scanf("%d%d",&n,&q);
      |     ~~~~~^~~~~~~~~~~~~~
Main.cpp:41:31: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |     for(int i=1;i<=n;++i)scanf("%d",a+i),at[a[i]]=i;
      |                          ~~~~~^~~~~~~~~~
Main.cpp:46:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |         scanf("%d%d",tt+i,ii+i);
      |         ~~~~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 40
• Subtask 3: 25 / 25
• Subtask 4: 0 / 25