loj 6285 series block entry 9

 

Solution: block. Wow, cancer questions ORZ, submitted several pages of TLE, but is a good question. The first discrete reprocessing. A mode where there are three sections: section prior ①L R and L and the block after block portion ②R. The mode number between the range block ③L, R. The mode between each two preprocessing block, side blocks violence, metaphysical block size opening.

 

Code:

#include<bits/stdc++.h>
using namespace std;
const int maxn=100010;
int w[maxn],scatter[maxn],n,block,cnt,dp[maxn/50][maxn/50],nn,t[maxn];
vector<int> v[maxn];
map<int,int>imapi;
int get(int x);
void pre(int x);
int check(int l,int r);
int find(int l,int r,int w);
int main()
{
  int i,l,r;
  scanf("%d",&n);
  block=50;
  cnt=n/block;
  if(n%block) cnt++;
  for(i=1;i<=n;i++)
   {
    scanf("%d",&w[i]);
    if(!imapi[w[i]])
     {
        imapi[w[i]]=++nn;
        scatter[nn]=w[i];
     }
    w[i]=imapi[w[i]];
    v[w[i]].push_back(i);
   }
  for(i=1;i<=cnt;i++) pre(i);
  for(i=0;i<n;i++)
  {
    scanf("%d%d",&l,&r);
    int index=check(l,r);
    printf("%d\n",scatter[index]);
  }
  system("pause");
  return 0;
}
int get(int x)
{return (x-1)/block+1;}
int find(int l,int r,int w)
{return upper_bound(v[w].begin(),v[w].end(),r)-lower_bound(v[w].begin(),v[w].end(),l);}
void pre(int x)
{
  memset(t,0,sizeof(t));
  int index,i,mmax=0,ans=0;
  for(i=(x-1)*block+1;i<=n;i++)
  {
    index=get(i);
    t[w[i]]++;
    if(t[w[i]]>mmax||(t[w[i]]==mmax&&scatter[w[i]]<scatter[ans]))
      mmax=t[w[i]],ans=w[i];
    dp[x][index]=ans;
  }
}
int check(int l,int r)
{
  int i,pre,end,ans=0,mmax=0,x;
  pre=get(l);end=get(r);
  if(pre==end)
   {
    for(i=l;i<=r;i++)
     {
       x=find(l,r,w[i]);
       if(x>mmax||(x==mmax&&scatter[w[i]]<scatter[ans]))
        mmax=x,ans=w[i];
     }
   }
   else
   {
    ans=dp[get(l)+1][get(r)-1];
    mmax=find(l,r,ans);
    for(i=l;i<=min(n,pre*block);i++)
     {
       x=find(l,r,w[i]);
       if(x>mmax||(x==mmax&&scatter[w[i]]<scatter[ans]))
         mmax=x,ans=w[i];
     }
    for(i=(end-1)*block+1;i<=r;i++)
     {
       x=find(l,r,w[i]);
       if(x>mmax||(x==mmax&&scatter[w[i]]<scatter[ans]))
         mmax=x,ans=w[i];
     }
   }
   return ans;
}