Submission #424258

#	Time	Username	Problem	Language	Result	Execution time	Memory
424258		Antekb	Shortcut (IOI16_shortcut)	C++14	31 / 100	2080 ms	452 KiB

shortcut

#include "shortcut.h"
#include<bits/stdc++.h>
#define st first
#define nd second
using namespace std;
const int N=3005;
typedef long long ll;
const ll INF=1e18;
struct kol{
	deque<pair<ll, int> > Q;
	void push(ll a){
		int sum=1;
		while(Q.size() && Q.back().st>a){
			sum+=Q.back().nd;
			Q.pop_back();
		}
		Q.push_back({a, sum});
	}
	void pop(){
		if(!--Q.front().nd)Q.pop_front();
	}
	ll maks(){
		if(!Q.size())return -INF;
		return Q.front().st;
	}
};
ll lew[N], pra[N], tab[N], dist[N], dist2[N], lew2[N], pra2[N];
int C;
ll calc(int a, int b){
	dist[a]=lew[a];
	dist[b]=pra[b];
	ll ans=max(pra2[b], lew2[a]);
	int j=a;
	kol q;
	q.push(tab[a]+dist[a]);
	//cout<<a<<" "<<b<<"\n";
	for(int i=a; i<=b; i++){
		/*while(j<b && tab[j+1]-tab[i]>=tab[b]-tab[j+1]+C+tab[i]-tab[a]){
			q.push(tab[j]+dist[j]);
		}
		q.pop();
		ans=max(ans, q.maks());*/
		for(int j=i+1; j<=b; j++){
			//cout<<i<<j<<" "<<dist[i]<<" "<<dist[j]<<" "<<tab[j]-tab[i]<<" "<<tab[b]-tab[j]+C+tab[i]-tab[a]<<"\n";
			ans=max(ans, dist[i]+dist[j]+min(tab[j]-tab[i], tab[b]-tab[j]+C+tab[i]-tab[a]));
		}
	}
	dist[a]=dist2[a];
	dist[b]=dist2[b];
	//cout<<a<<" "<<b<<" "<<ans<<"\n";
	return ans;
}
long long find_shortcut(int n, std::vector<int> l, std::vector<int> d, int c)
{
	C=c;
	for(int i=1; i<n; i++){
		tab[i]=tab[i-1]+l[i-1];
	}
	for(int i=0; i<n; i++){
		dist[i]=dist2[i]=d[i];
		lew[i]=d[i];
		if(i){
			lew[i]=max(lew[i], lew[i-1]+l[i-1]);
			lew2[i]=max(lew2[i-1], lew[i-1]+d[i]+l[i-1]);
		}
	}
	for(int i=n-1; i>=0; i--){
		pra[i]=d[i];
		if(i+1<n){
			pra[i]=max(pra[i], pra[i+1]+l[i]);
			pra2[i]=max(pra2[i+1], pra[i+1]+d[i]+l[i]);
		}
	}
	ll ans=INF;
	for(int i=0; i<n; i++){
		for(int j=i+1; j<n; ++j){
			ans=min(ans, calc(i, j));
		}
	}
    return ans;
}

Compilation message (stderr)

shortcut.cpp: In function 'll calc(int, int)':
shortcut.cpp:33:6: warning: unused variable 'j' [-Wunused-variable]
   33 |  int j=a;
      |      ^

• Subtask 1: 9 / 9
• Subtask 2: 14 / 14
• Subtask 3: 8 / 8
• Subtask 4: 0 / 7
• Subtask 5: 0 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3