Submission #96913

#	Time	Username	Problem	Language	Result	Execution time	Memory
96913		youngyojun	Shortcut (IOI16_shortcut)	C++11	71 / 100	2035 ms	3248 KiB

shortcut

#include "shortcut.h"
#include <bits/stdc++.h>
#define INFLL (0x3f3f3f3f3f3f3f3fll)
using namespace std;
typedef long long ll;
inline void upmin(ll &a, ll b) { if(b < a) a = b; }
inline void upmax(ll &a, ll b) { if(a < b) a = b; }

const int MAXN = 1000055;

ll Mx[MAXN], Mn[MAXN];
ll X[MAXN], L[MAXN];
int O[MAXN];

int N; ll K, Ans;

bool isp(ll Y) {
	ll xymx = -INFLL, xymn = INFLL, yxmx = -INFLL, yxmn = INFLL;
	fill(Mx, Mx+N, -INFLL);
	fill(Mn, Mn+N, INFLL);
	for(int i = 0; i < N; i++) for(int j = i+1; j < N; j++) {
		if(L[i]-X[i] <= Y-X[j]-L[j]) continue;
		upmin(xymn, Y-K + X[i]-L[i] + X[j]-L[j]);
		upmax(xymx, K-Y + X[i]+L[i] + X[j]+L[j]);
		upmin(yxmn, Y-K + X[j]-L[j] - (X[i]+L[i]));
		upmax(yxmx, K-Y + X[j]+L[j] - (X[i]-L[i]));
	}
	/*
	for(int oi = 0, i, j = 1; j < N; j++) {
		upmax(Mx[j], Mx[j-1]); upmin(Mn[j], Mn[j-1]);
		for(ll t = Y-X[j]-L[j]; oi < N; oi++) {
			i = O[oi];
			if(L[i]-X[i] <= t) break;
			upmax(Mx[max(i+1, j)], X[i]+L[i]);
			upmin(Mn[max(i+1, j)], X[i]-L[i]);
		}
		upmin(xymn, Y-K + Mn[j] + X[j]-L[j]);
		upmax(xymx, K-Y + Mx[j] + X[j]+L[j]);
		upmin(yxmn, Y-K - Mx[j] + X[j]-L[j]);
		upmax(yxmx, K-Y - Mn[j] + X[j]+L[j]);
	}
	*/
	for(int s = 0; s < N; s++) for(int e = s+1; e < N; e++) {
		if(X[s]+X[e] < xymx || xymn < X[s]+X[e]) continue;
		if(X[e]-X[s] < yxmx || yxmn < X[e]-X[s]) continue;
		return true;
	}
	for(int s = 0, xymxi = N-1, xymni = N-1, yxmxi = 0, yxmni = 0; s < N; s++) {
		for(ll t = xymx-X[s]; xymxi && t <= X[xymxi-1]; xymxi--);
		for(ll t = xymn-X[s]; 0 <= xymni && t < X[xymni]; xymni--);
		for(ll t = yxmx+X[s]; yxmxi < N && X[yxmxi] < t; yxmxi++);
		for(ll t = yxmn+X[s]; yxmni+1 < N && X[yxmni+1] <= t; yxmni++);
		if(X[xymxi] < xymx-X[s] || yxmn+X[s] < X[yxmni]) continue;
		if(max(xymxi, yxmxi) <= min(xymni, yxmni)) return true;
	}
	return false;
}

ll getAns() {
	ll mx = -INFLL;
	for(int i = 0; i < N; i++) {
		upmax(Ans, X[i]+L[i] + mx);
		upmax(mx, L[i]-X[i]);
	}
	iota(O, O+N, 0); sort(O, O+N, [&](int a, int b) {
		return L[a]-X[a] > L[b]-X[b];
	});
	ll s = 1, e = Ans;
	for(ll m; s < e;) {
		m = (s+e) >> 1;
		if(isp(m)) e = m;
		else s = m+1;
	}
	return s;
}

long long find_shortcut(int n, std::vector<int> l, std::vector<int> d, int c) {
	::N = n; ::K = c;
	for(int i = 1; i < N; i++) ::X[i] = ::X[i-1] + l[i-1];
	for(int i = 0; i < N; i++) ::L[i] = d[i];
    return getAns();
}

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