Submission #59170

#	Time	Username	Problem	Language	Result	Execution time	Memory
59170		TadijaSebez	Roller Coaster Railroad (IOI16_railroad)	C++11	100 / 100	216 ms	161924 KiB

railroad

#include <stdio.h>
#include <vector>
#include <algorithm>
using namespace std;
#define pb push_back
#define mp make_pair
#define ll long long
const int inf=1e9+7;
struct Event
{
	int x,t,id;
	Event(int a, int b, int c){ x=a,t=b,id=c;}
	bool operator < (Event b) const { return x<b.x || (x==b.x && t<b.t);}
};
struct Edge
{
	int u,v,w;
	Edge(int a, int b, int c){ u=a,v=b,w=c;}
	bool operator < (Edge b) const { return w<b.w;}
};
const int N=200050;
int p[N];
void init(){ for(int i=0;i<N;i++) p[i]=i;}
int Find(int x){ return p[x]==x?x:p[x]=Find(p[x]);}
void Union(int x, int y){ p[Find(x)]=Find(y);}
int max(int a, int b){ return a>b?a:b;}
ll plan_roller_coaster(vector<int> s, vector<int> t)
{
	int n=s.size(),i;
	vector<Event> events;
	for(i=0;i<n;i++) events.pb(Event(s[i],1,i+1)),events.pb(Event(t[i],-1,i+1));
	events.pb(Event(inf,1,n+1));
	events.pb(Event(1,-1,n+1));
	int balance=0;
	ll sol=0;
	init();
	sort(events.begin(),events.end());
	vector<Edge> edges;
	for(i=0;i<events.size()-1;i++)
	{
		int len=events[i+1].x-events[i].x;
		balance+=events[i].t;
		//printf("%i %i %i %i %i\n",events[i].x,len,balance,events[i].id,events[i+1].id);
		sol+=(ll)max(0,balance)*len;
		if(balance==0 && len>0) edges.pb(Edge(events[i].id,events[i+1].id,len));
		else Union(events[i].id,events[i+1].id);
	}
	sort(edges.begin(),edges.end());
	for(i=0;i<edges.size();i++)
	{
		//printf("%i %i %i %i %i\n",edges[i].u,edges[i].v,edges[i].w,Find(edges[i].u),Find(edges[i].v));
		if(Find(edges[i].u)!=Find(edges[i].v))
		{
			sol+=edges[i].w;
			Union(edges[i].u,edges[i].v);
		}
	}
	return sol;
}
/*int main()
{
	int n,i;
	vector<int> s,t;
	scanf("%i",&n);
	s.resize(n);t.resize(n);
	for(i=0;i<n;i++) scanf("%i %i",&s[i],&t[i]);
	printf("%lld\n",plan_roller_coaster(s,t));
	return 0;
}*/

Compilation message (stderr)

railroad.cpp: In function 'long long int plan_roller_coaster(std::vector<int>, std::vector<int>)':
railroad.cpp:39:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<events.size()-1;i++)
          ~^~~~~~~~~~~~~~~~
railroad.cpp:49:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<edges.size();i++)
          ~^~~~~~~~~~~~~

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