Submission #151650

#	Time	Username	Problem	Language	Result	Execution time	Memory
151650		qkxwsm	Shortcut (IOI16_shortcut)	C++14	71 / 100	2053 ms	11928 KiB

shortcut

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

using namespace std;

template<class T, class U>
void ckmin(T &a, U b)
{
	if (a > b) a = b;
}
template<class T, class U>
void ckmax(T &a, U b)
{
	if (a < b) a = b;
}

#define y1 qwertyuiop
#define y2 asdfghjkl
#define MP make_pair
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define FOR(i, a, b) for (auto i = (a); i < (b); i++)
#define FORD(i, a, b) for (auto i = (a) - 1; i >= (b); i--)
#define SZ(x) ((int) ((x).size()))
#define ALL(x) (x).begin(), (x).end()
#define MAXN 1000013
#define INF 1000000007
#define LLINF 2696969696969696969

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpi;
typedef vector<pll> vpl;

int N;
ll D;
pll arr[MAXN];
vl pts;
ll fen[2][MAXN];
set<ll> vals;

void init()
{
	FOR(i, 0, SZ(pts) + 1)
	{
		fen[0][i] = LLINF;
		fen[1][i] = -LLINF;
	}
}
void update(int w, int idx, ll v)
{
	for (int e = idx + 1; e <= SZ(pts); e += e & (-e))
	{
		if (w == 0) ckmin(fen[w][e], v);
		else ckmax(fen[w][e], v);
	}
	return;
}
ll query(int w, int idx)
{
	ll res = (w ? -LLINF : LLINF);
	for (int e = idx + 1; e; e -= e & (-e))
	{
		if (w == 0) ckmin(res, fen[w][e]);
		else ckmax(res, fen[w][e]);
	}
	return res;
}

bool check(ll s)
{
	pll x = {-LLINF, LLINF}, y = {-LLINF, LLINF};
	init();
	FOR(i, 0, N)
	{
		ll c = arr[i].fi, d = arr[i].se;
	 	int idx = LB(ALL(pts), c + d - s) - pts.begin() - 1;
		ll mx = query(1, idx), mn = query(0, idx);
		ckmax(x.fi, mx + c + d);
		ckmin(x.se, mn + c - d);
		ckmax(y.fi, mx - c + d);
		ckmin(y.se, mn - c - d);
		idx = LB(ALL(pts), c - d) - pts.begin();
		update(1, idx, c + d);
		update(0, idx, c - d);
	}
	// FOR(i, 0, N)
	// {
	// 	ll a = arr[i].fi, b = arr[i].se;
	// 	FOR(j, i + 1, N)
	// 	{
	// 		ll c = arr[j].fi, d = arr[j].se;
	// 		if (d + c + b - a <= s) continue;
	// 		// you need d+c+b-a > s <=> a-b < d+c-s.
	// 		// store min value of a-b and max value of a+b
	// 		ckmax(x.fi, a + b + c + d);
	// 		ckmin(x.se, a - b + c - d);
	// 		ckmax(y.fi, a + b - c + d);
	// 		ckmin(y.se, a - b - c - d);
	// 		//update(a + c - rem, a + c + rem, a - c - rem, a - c + rem)
	// 	}
	// }
	x.fi += (D - s);
	y.fi += (D - s);
	x.se += (s - D);
	y.se += (s - D);
	vals.clear();
	FORD(i, N, 0)
	{
		ll m = arr[i].fi;
		ll lt = max(x.fi - m, m - y.se), rt = min(x.se - m, m - y.fi);
		auto it = vals.LB(lt);
		if (it != vals.end() && *it <= rt) return true;
		vals.insert(m);
	}
	// cerr << s << ' ' << x.fi << ' ' << x.se << ' ' << y.fi << ' ' << y.se << endl;
	// FOR(i, 0, N)
	// {
	// 	ll m = arr[i].fi;
	// 	FOR(j, i + 1, N)
	// 	{
	// 		ll n = arr[j].fi;
	// 		// cerr << m + n << ',' << m - n << endl;
	// 		if (x.fi <= m + n && m + n <= x.se && y.fi <= m - n && m - n <= y.se) return true;
	// 	}
	// }
	return false;
}
ll find_shortcut(int n, vi l, vi d, int vs)
{
	N = n; D = vs;
	l.insert(l.begin(), 0);
	FOR(i, 0, N)
	{
		arr[i].fi = l[i];
		arr[i].se = d[i];
	}
	FOR(i, 1, N)
	{
		arr[i].fi += arr[i - 1].fi;
	}
	// FOR(i, 0, N)
	// {
	// 	cerr << arr[i].fi << ' ' << arr[i].se << endl;
	// }
	FOR(i, 0, N)
	{
		pts.PB(arr[i].fi - arr[i].se);
	}
	sort(ALL(pts));
	pts.erase(unique(ALL(pts)), pts.end());
	ll lo = 0, hi = LLINF;
	while(hi > lo)
	{
		ll mid = (hi + lo) >> 1;
		if (check(mid)) hi = mid;
		else lo = mid + 1;
	}
    return lo;
}

• 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