Submission #945237

#	Time	Username	Problem	Language	Result	Execution time	Memory
945237		Lalic	Roller Coaster Railroad (IOI16_railroad)	C++17	100 / 100	530 ms	71868 KiB

railroad

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

#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define allr(x) x.rbegin(), x.rend()
#define mp make_pair

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 2e5+10;
const int INF = 0x3f3f3f3f;
const ll LINF = 0x3f3f3f3f3f3f3f3f;
const int MOD = 1e9+7;

void dfs(int ver, int val, vector<vector<int>>& adj, vector<int>& cmp){
	cmp[ver]=val;
	
	for(auto u : adj[ver])
		if(!cmp[u]) dfs(u, val, adj, cmp);
}

int pai[MAXN], peso[MAXN];

int find(int x){ return (pai[x]==x ? x : pai[x]=find(pai[x])); }
void join(int a, int b){
	a=find(a); b=find(b);
	
	if(a==b) return;
	
	if(peso[a]>peso[b]) swap(a, b);
	pai[a]=b;
	peso[b]=max(peso[b], peso[a]+1);
}

long long plan_roller_coaster(vector<int> s, vector<int> t) {
    vector<int> arr;
    for(auto u : s) arr.pb(u);
    for(auto u : t) arr.pb(u);
    sort(all(arr));
    arr.erase(unique(all(arr)), arr.end());
    
    int n=(int)arr.size();
    
    map<int, int> mp;
    vector<int> g(n, 0);
    for(int i=0;i<n;i++) mp[arr[i]]=i;
    
    vector<vector<int>> adj(n);
    adj[n-1].pb(0);
    g[n-1]++; g[0]--;
    
    for(int i=0;i<(int)s.size();i++){
		g[mp[s[i]]]++; g[mp[t[i]]]--;
		adj[mp[s[i]]].pb(mp[t[i]]);
	}
	
	ll ans=0ll;
	
	for(int i=0;i<n-1;i++){
		if(g[i]>0) adj[i+1].pb(i), ans+=(ll)g[i]*(ll)(arr[i+1]-arr[i]), g[i+1]+=g[i], g[i]=0;
		else if(g[i]<0) adj[i].pb(i+1), g[i+1]+=g[i], g[i]=0;
	}
	
	int cnt=0;
	vector<int> cmp(n, 0);
	for(int i=0;i<n;i++)
		if(!cmp[i]) dfs(i, ++cnt, adj, cmp);
		
	for(int i=1;i<=cnt;i++) pai[i]=i;
	
	vector<pair<int, pii>> edge;
	for(int i=0;i<n-1;i++)
		if(cmp[i]!=cmp[i+1]) edge.pb({arr[i+1]-arr[i], {cmp[i], cmp[i+1]}});
	
	sort(all(edge));
	
	for(auto u : edge){
		if(find(u.se.fi)!=find(u.se.se)){
			join(u.se.fi, u.se.se);
			ans+=u.fi;
		}
	}
	
	return ans;
}

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