Submission #96938

#	Time	Username	Problem	Language	Result	Execution time	Memory
96938		youngyojun	Shortcut (IOI16_shortcut)	C++11	71 / 100	2039 ms	4344 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 = 1000005;

ll X[MAXN], L[MAXN];
int O[MAXN], OJ[MAXN];

int N; ll K, Ans;

bool isp(ll Y) {
	ll xymx = -INFLL, xymn = INFLL, yxmx = -INFLL, yxmn = INFLL;
	ll mn[2] = {INFLL, INFLL}, mx[2] = {-INFLL, -INFLL};
	int mni[2] = {-1, -1}, mxi[2] = {-1, -1};
	for(int oi = 0, i, oj = 0, j; oj < N; oj++) {
		j = OJ[oj];
		for(ll t = Y-X[j]-L[j], c; oi < N; oi++) {
			i = O[oi]; c = X[i]-L[i];
			if(-c <= t) break;
			if(c < mn[0]) { swap(mn[0], c); swap(mni[0], i); }
			if(c < mn[1]) { swap(mn[1], c); swap(mni[1], i); }
			i = O[oi]; c = X[i]+L[i];
			if(mx[0] < c) { swap(mx[0], c); swap(mxi[0], i); }
			if(mx[1] < c) { swap(mx[1], c); swap(mxi[1], i); }
		}
		ll rmx = j == mxi[0] ? mx[1] : mx[0];
		ll rmn = j == mni[0] ? mn[1] : mn[0];
		ll a = Y-K + X[j]-L[j], b = K-Y + X[j]+L[j];
		upmin(xymn, a+rmn); upmax(xymx, b+rmx);
		upmin(yxmn, a-rmx); upmax(yxmx, b-rmn);
		if(xymn < xymx || yxmn < yxmx) return false;
	}
	for(int s = 0, e = 0; s < N; s++) {
		ll rmn = max(xymx-X[s], yxmx+X[s]);
		ll rmx = min(xymn-X[s], yxmn+X[s]);
		if(rmx < rmn) continue;
		for(e = 0; e < N; e++)
			if(rmn <= X[e] && X[e] <= rmx) return true;
		for(; e+1 < N && X[e] < rmn; e++);
		for(; e && rmx < X[e]; e--);
		if(rmn <= X[e]) 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];
	});
	iota(OJ, OJ+N, 0); sort(OJ, OJ+N, [&](int a, int b) {
		return X[a]+L[a] < X[b]+L[b];
	});
	ll a = 0, b = 0;
	for(int i = 0; i < N; i++) {
		ll c = L[i];
		if(a < c) swap(a, c);
		if(b < c) swap(b, c);
	}
	ll s = a+b, 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