Submission #134822

#	Time	Username	Problem	Language	Result	Execution time	Memory
134822		Mahdi_Jfri	Roller Coaster Railroad (IOI16_railroad)	C++14	34 / 100	390 ms	17656 KiB

railroad

#include "railroad.h"
#include<bits/stdc++.h>

using namespace std;

#define ll long long
#define pb push_back
#define bit(a , b) (((a)>>(b))&1)

const int maxn = 2e5 + 20;
const int maxm = (1 << 16) + 20;

int ind[maxn] , s[maxn] , t[maxn] , n;

ll dp[maxm][20];

ll solve()
{
	memset(dp , 63 , sizeof dp);
	int hlp = (1 << n);
	for(int mask = 1; mask < hlp; mask++)
		for(int i = 0; i < n; i++)
			if(bit(mask , i))
			{
				if(mask == (1 << i))
				{
					dp[mask][i] = 0;
					break;
				}

				for(int j = 0; j < n; j++)
					if(bit(mask ^ (1 << i) , j))
						dp[mask][i] = min(dp[mask][i] , dp[mask ^ (1 << i)][j] + max(0 , t[j] - s[i]));
			}

	ll ans = *min_element(dp[hlp - 1] , dp[hlp - 1] + n);
	return ans;
}

bool cmp(int x , int y)
{
	return t[x] < t[y];
}

long long plan_roller_coaster(vector<int> S, vector<int> T)
{
    n = (int)S.size();
	for(int i = 0; i < n; i++)
		s[i] = S[i] , t[i] = T[i] , ind[i] = i;

	if(n <= 16)
		return solve();

	sort(ind , ind + n , cmp);

	set<pair<int , int> > st;
	for(int i = 0; i < n; i++)
	{
		s[i] = S[ind[i]];
		t[i] = T[ind[i]];
		st.insert({s[i] , i});
	}

	ll res = 0;
	for(int i = n - 1; i > 0; i--)
	{
		st.erase({s[i] , i});
		auto it = st.lower_bound(make_pair(t[i] , -1e9));
		if(it == st.end())
			it--;
		int x = it -> second;
		st.erase(it);
		res += max(0 , t[i] - s[x]);
		s[x] = s[i];
		st.insert({s[x] , x});
	}

	return res;
}

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