Submission #97033

#	Time	Username	Problem	Language	Result	Execution time	Memory
97033		youngyojun	Shortcut (IOI16_shortcut)	C++11	100 / 100	1601 ms	90320 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 Mx0[MAXN], Mx1[MAXN];
ll X[MAXN], L[MAXN], TP[MAXN], TM[MAXN];
int O[MAXN], OJ[MAXN];

int N; ll K, Ans;

bool isp(ll Y) {
	ll xymx = -INFLL, xymn = INFLL, yxmx = -INFLL, yxmn = INFLL, rmn, rmx;
	for(int oi = 0, oj = 0, j; oj < N; oj++) {
		j = OJ[oj]; ll t = Y-TP[j];
		for(; oi < N && t < TM[O[oi]]; oi++);
		if(!oi || (1 == oi && j == O[0])) continue;
		rmx = TP[j] == Mx0[oi-1] ? Mx1[oi-1] : Mx0[oi-1];
		rmn = -(j == O[0] ? TM[O[1]] : TM[O[0]]);
		ll a = Y-K - TM[j], b = K-Y + TP[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++) {
		rmn = max(xymx-X[s], yxmx+X[s]);
		rmx = min(xymn-X[s], yxmn+X[s]);
		if(rmx < rmn) continue;
		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]);
		TP[i] = X[i]+L[i];
		TM[i] = L[i]-X[i];
	}
	iota(O, O+N, 0); sort(O, O+N, [&](int a, int b) {
		return TM[a] > TM[b];
	});
	iota(OJ, OJ+N, 0); sort(OJ, OJ+N, [&](int a, int b) {
		return TP[a] < TP[b];
	});
	Mx0[0] = Mx1[0] = -INFLL;
	for(int oi = 0, i; oi < N; oi++) {
		if(oi) {
			Mx0[oi] = Mx0[oi-1];
			Mx1[oi] = Mx1[oi-1];
		}
		i = O[oi]; ll c = TP[i];
		if(Mx0[oi] < c) swap(Mx0[oi], c);
		if(Mx1[oi] < c) swap(Mx1[oi], c);
	}
	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: 22 / 22
• Subtask 7: 4 / 4
• Subtask 8: 3 / 3