Submission #284602

#	Time	Username	Problem	Language	Result	Execution time	Memory
284602		MKopchev	Meetings (IOI18_meetings)	C++14	19 / 100	859 ms	235128 KiB

meetings

#include "meetings.h"
#include<bits/stdc++.h>
using namespace std;

const int nmax=5e3+42;

long long pref[nmax][nmax],suff[nmax][nmax];//left -> start, right-> to

const int SZ=4e5+42;

struct info
{
    int pref,suff,best,sz;
};

info tree[SZ];

info my_merge(info le,info ri)
{
    info ret;

    ret.sz=le.sz+ri.sz;

    ret.pref=le.pref;
    if(le.pref==le.sz)ret.pref+=ri.pref;

    ret.suff=ri.suff;
    if(ri.suff==ri.suff)ret.suff+=le.suff;

    ret.sz=le.sz+ri.sz;

    ret.best=max(le.best,ri.best);
    ret.best=max(ret.best,le.suff+ri.pref);

    return ret;
}

void update(int node,int l,int r,int pos,int val)
{
    if(l==r)
    {
        tree[node].sz=1;
        tree[node].pref=(val==0?1:0);
        tree[node].suff=tree[node].pref;
        tree[node].best=tree[node].pref;
        return;
    }
    int av=(l+r)/2;

    if(pos<=av)update(node*2,l,av,pos,val);
    else update(node*2+1,av+1,r,pos,val);

    tree[node]=my_merge(tree[node*2],tree[node*2+1]);
}

info query(int node,int l,int r,int lq,int rq)
{
    if(l==lq&&r==rq)return tree[node];

    int av=(l+r)/2;

    if(rq<=av)return query(node*2,l,av,lq,rq);

    if(av<lq)return query(node*2+1,av+1,r,lq,rq);

    return my_merge(query(node*2,l,av,lq,av),query(node*2+1,av+1,r,av+1,rq));
}

std::vector<long long> minimum_costs(std::vector<int> H, std::vector<int> L,
                                     std::vector<int> R)
{
    int n=H.size();
    if(H.size()<=5000)
    {

    for(int le=0;le<n;le++)
    {
        int maxi=H[le];

        suff[le][le]=maxi;

        for(int ri=le+1;ri<n;ri++)
        {
            maxi=max(maxi,H[ri]);
            suff[le][ri]=suff[le][ri-1]+maxi;
        }
    }

    for(int le=0;le<n;le++)
    {
        int maxi=H[le];

        pref[le][le]=maxi;

        for(int ri=le-1;ri>=0;ri--)
        {
            maxi=max(maxi,H[ri]);
            pref[le][ri]=pref[le][ri+1]+maxi;
        }
    }
    /*
    for(int le=0;le<n;le++)
        for(int ri=0;ri<n;ri++)
            cout<<le<<" "<<ri<<" -> "<<pref[le][ri]<<" "<<suff[le][ri]<<endl;
    */
    vector<long long> outp={};

    for(int i=0;i<L.size();i++)
    {
        outp.push_back(1e18);

        for(int j=L[i];j<=R[i];j++)
        {
            //cout<<L[i]<<" "<<R[i]<<" "<<j<<" -> "<<pref[j][L[i]]<<" "<<suff[j][R[i]]<<" "<<H[j]<<endl;

            outp[i]=min(outp[i],pref[j][L[i]]+suff[j][R[i]]-H[j]);
        }
    }
    return outp;

    }
    else
    {
        for(int i=0;i<n;i++)
            update(1,0,n-1,i,H[i]-1);

        vector<long long> outp={};

        for(int i=0;i<L.size();i++)
        {
            outp.push_back(2*(R[i]-L[i]+1));

            outp[i]=outp[i]-query(1,0,n-1,L[i],R[i]).best;
        }

        return outp;
    }
}

Compilation message (stderr)

meetings.cpp: In function 'info my_merge(info, info)':
meetings.cpp:28:15: warning: self-comparison always evaluates to true [-Wtautological-compare]
   28 |     if(ri.suff==ri.suff)ret.suff+=le.suff;
      |        ~~~~~~~^~~~~~~~~
meetings.cpp: In function 'std::vector<long long int> minimum_costs(std::vector<int>, std::vector<int>, std::vector<int>)':
meetings.cpp:108:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  108 |     for(int i=0;i<L.size();i++)
      |                 ~^~~~~~~~~
meetings.cpp:129:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  129 |         for(int i=0;i<L.size();i++)
      |                     ~^~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 15 / 15
• Subtask 3: 0 / 17
• Subtask 4: 0 / 24
• Subtask 5: 0 / 40