Submission #134718

#	Time	Username	Problem	Language	Result	Execution time	Memory
134718		Mahdi_Jfri	Shortcut (IOI16_shortcut)	C++14	38 / 100	236 ms	2552 KiB

shortcut

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

using namespace std;

#define ll long long
#define pb push_back

const int maxn = 5e2 + 20;

ll s[maxn] , pf[maxn] , sf[maxn] , mxp[maxn] , mxs[maxn];
int d[maxn];

ll mx[maxn][maxn];

ll fn(int a , int b)
{
	if(a > b)
		swap(a , b);

	return s[b] - s[a];
}

long long find_shortcut(int n, std::vector<int> L, std::vector<int> D, int c)
{
	for(int i = 0; i < n; i++)
	{
		d[i] = D[i];
		if(i)
			s[i] = L[i - 1] + s[i - 1];
	}

	memset(pf , -63 , sizeof pf);
	memset(sf , -63 , sizeof sf);
	memset(mxp , -63 , sizeof mxp);
	memset(mxs , -63 , sizeof mxs);
	for(int i = 0; i < n; i++)
	{
		if(i)
		{
			pf[i] = pf[i - 1];
			mxp[i] = mxp[i - 1];
			pf[i] = max(pf[i - 1] , mxp[i - 1] + d[i] + s[i]);
		}

		mxp[i] = max(mxp[i] , d[i] - s[i]);
	}

	for(int i = n - 1; i >= 0; i--)
	{
		sf[i] = max(sf[i + 1] , d[i] - s[i] + mxs[i + 1]);
		mxs[i] = max(mxs[i + 1] , d[i] + s[i]);
	}

	memset(mx , -63 , sizeof mx);
	for(int i = 0; i < n; i++)
		for(int j = i + 1; j < n; j++)
			mx[i][j] = max(mx[i][j - 1] , d[j - 1] - s[j - 1]);

	ll ans = pf[n - 1];
	for(int l = 0; l < n; l++)
		for(int r = l + 1; r < n; r++)
		{
			if(c > s[r] - s[l])
				continue;

			ll res = max(pf[l] , sf[r]);
			res = max(res , mxp[l] + mxs[r] + c - (s[r] - s[l]));

			int pt = l + 1;
			ll Mx = -1e18;
			for(int v = l + 1; v < r; v++)
			{
				ll dis1 = min(s[v] - s[l] , s[r] - s[v] + c) + mxp[l] + s[l] + d[v];
				ll dis2 = min(s[r] - s[v] , s[v] - s[l] + c) + mxs[r] - s[r] + d[v];
				res = max(res , max(dis1 , dis2));

				while(pt < v && s[v] - s[pt] >= s[r] - s[v] + c + s[pt] - s[l])
				{
					Mx = max(Mx , s[pt] + d[pt]);
					pt++;
				}

				ll tmp = -1e18;
				for(int u = pt; u < v; u++)
					tmp = max(tmp , d[u] - s[u]);

				res = max(res , s[v] + mx[pt][v] + d[v]);
				res = max(res , s[r] - s[v] + c - s[l] + Mx + d[v]);
			}

			ans = min(ans , res);
		}

	return ans;
}

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