Submission #887355

#	Time	Username	Problem	Language	Result	Execution time	Memory
887355		abcvuitunggio	Dancing Elephants (IOI11_elephants)	C++17	100 / 100	3400 ms	16984 KiB

elephants

#include "elephants.h"
#include <bits/stdc++.h>
using namespace std;
const int sz=511,sz2=266,maxN=150000;
int n,l,x[maxN+1],idx[maxN+1],q,pos[maxN+1];
pair <int, int> nxt[maxN/sz+1][sz+sz2+1];
vector <int> v[maxN/sz+1];
void calc(int k){
    if (v[k].empty())
        return;
    int j=v[k].size()-1;
    for (int i=j;i>=0;i--){
        while (x[v[k][i]]+l<x[v[k][j]])
            j--;
        if (j==v[k].size()-1)
            nxt[k][i]={i,0};
        else{
            j++;
            nxt[k][i]={nxt[k][j].first,nxt[k][j].second+1};
        }
    }
}
void init(int N, int L, int X[]){
    n=N,l=L;
    for (int i=0;i<n;i++){
        x[i]=X[i];
        idx[i]=i;
    }
    sort(idx,idx+n,[](int i, int j){return x[i]<x[j];});
    for (int i=0;i*sz<n;i++){
        v[i].clear();
        for (int j=i*sz;j<min(i*sz+sz,n);j++){
            v[i].push_back(idx[j]);
            pos[idx[j]]=i;
        }
        calc(i);
    }
}
void reinit(){
    int j=0;
    for (int i=0;i*sz<n;i++){
        for (int k:v[i]){
            idx[j]=k;
            j++;
        }
    }
    for (int i=0;i*sz<n;i++){
        v[i].clear();
        for (int j=i*sz;j<min(i*sz+sz,n);j++){
            v[i].push_back(idx[j]);
            pos[idx[j]]=i;
        }
        calc(i);
    }
}
int update(int i, int y){
    q++;
    if (q%sz2==0)
        reinit();
    vector <int> tmp;
    int c=0;
    for (int j:v[pos[i]]){
        if (j!=i||c)
            tmp.push_back(j);
        else
            c=1;
    }
    swap(tmp,v[pos[i]]);
    calc(pos[i]);
    tmp.clear();
    x[i]=y;
    int newpos=-1;
    for (int j=0;j*sz<n;j++){
        int l=(j?x[v[j-1].back()]:-1),r=(j*sz+sz<n&&!v[j+1].empty()?x[v[j+1][0]]:1000000001);
        if (l<=y&&y<=r){
            newpos=j;
            break;
        }
    }
    pos[i]=newpos;
    c=0;
    for (int j:v[newpos]){
        if (x[j]>=y&&!c){
            tmp.push_back(i);
            c=1;
        }
        tmp.push_back(j);
    }
    if (!c)
        tmp.push_back(i);
    swap(v[newpos],tmp);
    calc(newpos);
    int j=0,cur=0,res=0,block=0;
    while (true){
        res+=nxt[block][cur].second;
        cur=nxt[block][cur].first;
        res++;
        j=max(j,block+1);
        while (j<=(n-1)/sz){
            if (v[j].empty()||x[v[j].back()]<=x[v[block][cur]]+l){
                j++;
                continue;
            }
            break;
        }
        if (j>(n-1)/sz)
            break;
        int lo=0,hi=v[j].size()-1,kq=-1;
        while (lo<=hi){
            int mid=(lo+hi)>>1;
            if (x[v[j][mid]]>x[v[block][cur]]+l){
                kq=mid;
                hi=mid-1;
            }
            else
                lo=mid+1;
        }
        cur=kq;
        block=j;
    }
    return res;
}

Compilation message (stderr)

elephants.cpp: In function 'void calc(int)':
elephants.cpp:15:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |         if (j==v[k].size()-1)
      |             ~^~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 16 / 16
• Subtask 3: 24 / 24
• Subtask 4: 47 / 47
• Subtask 5: 3 / 3