Submission #836722

#	Time	Username	Problem	Language	Result	Execution time	Memory
836722		oscar1f	Roller Coaster Railroad (IOI16_railroad)	C++17	100 / 100	494 ms	69180 KiB

railroad

#include<bits/stdc++.h>
#include "railroad.h"

using namespace std;
using ll=long long;

const ll MAX_TRANSFO=4*200*1000+5,INFINI=(ll)1000*1000*1000*1000*1000*1000;
ll nbTransfo,rep,nbInter;
ll seuil[MAX_TRANSFO],valNouv[MAX_TRANSFO],vraiVal[MAX_TRANSFO];
set<ll> listeInter;
ll valInter[MAX_TRANSFO];
unordered_map<ll,ll> transfo;
ll cumu[MAX_TRANSFO];
ll pere[MAX_TRANSFO];

ll find(ll pos) {
    if (pere[pos]!=pos) {
        pere[pos]=find(pere[pos]);
    }
    return pere[pos];
}

ll unir(ll deb,ll fin) {
    if (find(deb)!=find(fin)) {
        pere[find(deb)]=find(fin);
        return 1;
    }
    return 0;
}

ll plan_roller_coaster(vector<int> s,vector<int> t) {
    nbTransfo=s.size();
    for (ll i=0;i<nbTransfo;i++) {
        seuil[i]=s[i];
        listeInter.insert(seuil[i]);
        valNouv[i]=t[i];
        listeInter.insert(valNouv[i]);
    }
    seuil[nbTransfo]=INFINI;
    listeInter.insert(INFINI);
    valNouv[nbTransfo]=1;
    listeInter.insert(1);
    nbTransfo++;    
    for (ll i:listeInter) {
        vraiVal[nbInter]=i;
        transfo[i]=nbInter;
        nbInter++;
    }    
    for (ll i=0;i<nbInter;i++) {
        pere[i]=i;
    }
    for (ll i=0;i<nbTransfo;i++) {
        cumu[transfo[seuil[i]]]++;
        cumu[transfo[valNouv[i]]]--;
        unir(transfo[seuil[i]],transfo[valNouv[i]]);
    }
    vector<pair<ll,ll>> distTri;
    for (ll i=0;i<nbInter-1;i++) {
        cumu[i+1]+=cumu[i];
        rep+=(vraiVal[i+1]-vraiVal[i])*(max(cumu[i],(ll)0));
        if (cumu[i]!=0) {
            unir(i+1,i);
        }
        distTri.push_back({vraiVal[i+1]-vraiVal[i],i});
    }
    sort(distTri.begin(),distTri.end());
    for (auto i:distTri) {
        if (unir(i.second,i.second+1)==1) {
            rep+=i.first;
        }
    }
    return rep;
}

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 30 / 30
• Subtask 4: 36 / 36