Submission #388630

#	Time	Username	Problem	Language	Result	Execution time	Memory
388630		alishahali1382	Roller Coaster Railroad (IOI16_railroad)	C++14	100 / 100	279 ms	24580 KiB

railroad

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

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, int> pli;
#define debug(x) {cerr<<#x<<"="<<x<<"\n";}
#define debug2(x, y) {cerr<<#x<<", "<<#y<<" = "<<x<<", "<<y<<"\n";}
#define pb push_back
#define all(x) x.begin(), x.end()

const int inf=1000000010;
const ll INF=10000001000000000ll;
const int MAXN=400010;

int n, m, k;
int S[MAXN], T[MAXN], ps[MAXN];
int par[MAXN];
bool mark[MAXN];
// ll dp[1<<16][16];
vector<int> comp;
ll ans;

int getpar(int x){ return (par[x]==x?x:par[x]=getpar(par[x]));}

ll plan_roller_coaster(vector<int> s, vector<int> t){
	n=s.size();/*
	if (n<=16){
		for (int mask=1; mask<(1<<n); mask++){
			int v=__builtin_ctz(mask);
			if (mask==(1<<v)) dp[mask][v]=0;
			else{
				for (int v=0; v<n; v++) if (mask&(1<<v)){
					dp[mask][v]=INF;
					for (int u=0; u<n; u++) if (u!=v && mask&(1<<u))
						dp[mask][v]=min(dp[mask][v], dp[mask^(1<<v)][u] + max(0, t[u]-s[v]));
				}
			}
		}
		ll ans=INF;
		for (int i=0; i<n; i++) ans=min(ans, dp[(1<<n)-1][i]);
		return ans;
	}*/
	for (int i=1; i<=n; i++) S[i]=s[i-1], T[i]=t[i-1];
	S[0]=inf;
	T[0]=1;
	for (int i=0; i<=n; i++){
		comp.pb(T[i]);
		comp.pb(S[i]);
	}
	sort(all(comp));
	comp.resize(unique(all(comp))-comp.begin());
	m=comp.size();
	iota(par, par+m, 0);
	for (int i=0; i<=n; i++){
		S[i]=lower_bound(all(comp), S[i])-comp.begin();
		T[i]=lower_bound(all(comp), T[i])-comp.begin();
		par[getpar(S[i])]=getpar(T[i]);
		// debug2(S[i], T[i])
		ps[S[i]]++;
		ps[T[i]]--;
	}
	for (int i=1; i<m; i++) ps[i]+=ps[i-1];
	for (int i=0; i+1<m; i++) if (ps[i]){
		// debug2(i, comp[i])
		par[getpar(i)]=getpar(i+1);
		if (ps[i]>0) ans+=1ll*ps[i]*(comp[i+1]-comp[i]);
	}
	// debug(ans)
	vector<pair<ll, pii>> E;
	for (int i=0; i<=n; i++) mark[getpar(S[i])]=1;
	int last=-1;
	for (int i=0; i<m; i++) if (mark[getpar(i)]){
		if (last!=-1) E.pb({comp[i]-comp[last], {i, last}});
		last=i;
	}
	sort(all(E));
	for (auto p:E){
		int x=getpar(p.second.first), y=getpar(p.second.second);
		if (x!=y){
			par[x]=y;
			ans+=p.first;
		}
	}
	return ans;
}

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