Submission #1031046

#	Time	Username	Problem	Language	Result	Execution time	Memory
1031046		Warinchai	Roller Coaster Railroad (IOI16_railroad)	C++14	30 / 100	177 ms	17224 KiB

railroad

#include "railroad.h"
#include<bits/stdc++.h>
using namespace std;
int p[2000005],a[2000005];
int fp(int a){
    return p[a]==a?a:p[a]=fp(p[a]);
}
void un(int a,int b){
    p[fp(a)]=fp(b);
}
vector<int>ids;
map<int,int>mp;
long long plan_roller_coaster(std::vector<int> s, std::vector<int> t) {
    int n = (int) s.size();
    vector<int> ids;
    for(int i=0;i<n;i++){
        ids.push_back(s[i]);
        ids.push_back(t[i]);
    }
    ids.push_back(INT_MIN);
    sort(ids.begin(),ids.end());
    ids.erase(unique(ids.begin(),ids.end()),ids.end());
    int m=ids.size();
    for(int i=1;i<=m;i++)p[i]=i;
    for(int i=0;i<n;i++){
        s[i]=lower_bound(ids.begin(),ids.end(),s[i])-ids.begin();
        t[i]=lower_bound(ids.begin(),ids.end(),t[i])-ids.begin();
        un(s[i],t[i]);
        a[s[i]]++,a[t[i]]--;
    }
    int val=0;
    int ans=0;
    for(int i=1;i<m;i++){
        val+=a[i];
        if(val>1)ans+=(val-1)*(ids[i+1]-ids[i]);
        else if(val<1)un(i,i+1);
    }
    vector<pair<int,int>>edges;
    for(int i=1;i<m;i++){
        edges.push_back({ids[i+1]-ids[i],i});
    }
    sort(edges.begin(),edges.end());
    for(auto x:edges){
        if(fp(x.second)!=fp(x.second+1))un(x.second,x.second+1),ans+=(ids[x.second+1]-ids[x.second]);
    }
    return ans;
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 23
• Subtask 3: 30 / 30
• Subtask 4: 0 / 36