Submission #105528

#	Time	Username	Problem	Language	Result	Execution time	Memory
105528		polyfish	Shortcut (IOI16_shortcut)	C++14	0 / 100	2 ms	384 KiB

shortcut

//Pantyhose(black) + glasses = infinity

#include <bits/stdc++.h>
using namespace std;
 
#define debug(x) cerr << #x << " = " << x << '\n';
#define BP() cerr << "OK!\n";
#define PR(A, n) {cerr << #A << " = "; for (int _=1; _<=n; ++_) cerr << A[_] << ' '; cerr << '\n';}
#define PR0(A, n) {cerr << #A << " = "; for (int _=0; _<n; ++_) cerr << A[_] << ' '; cerr << '\n';}
#define FILE_NAME "data"

const int64_t INF = 1e18;
const int MAX_N = 1000002;

int n, idx1[MAX_N], idx2[MAX_N];
int64_t d[MAX_N], v[MAX_N], q[MAX_N], c;
vector<int64_t> b;

struct fenwick_tree {

	int n;
	vector<int64_t> bit;

	void init(int _n) {
		n = _n;
		bit.assign(n+1, -INF);
	}

	void upd(int idx, int64_t val) {
		for (; idx<=n; idx += idx & -idx)
			bit[idx] = max(bit[idx], val);
	}

	int64_t get(int idx) {
		int64_t res = -INF;

		for (; idx>0; idx -= idx & -idx)
			res = max(res, bit[idx]);

		return res;
	}

};

fenwick_tree bit1, bit2;

void init(int64_t x) {
	for (int i=0; i<n; ++i)
		idx2[i] = lower_bound(b.begin(), b.end(), v[i]-d[i]-x-1) - b.begin() + 1;
}

bool check(int64_t x) {
	int64_t l1, r1, l2, r2;
	l1 = l2 = -INF;
	r1 = r2 = INF;

	bit1.init(2*n);
	bit2.init(2*n);

	init(x);

	for (int i=n-1; i>=0; --i) {

		int64_t tmp1 = bit1.get(idx2[i]), tmp2 = bit2.get(idx2[i]);

		l1 = max(l1, tmp1+d[i]-x+c+v[i]);
		r1 = min(r1, -tmp2+d[i]+x-c-v[i]);
		l2 = max(l2, tmp2+d[i]-x+c+v[i]);
		r2 = min(r2, -tmp1+d[i]+x-c-v[i]);

		// if (i==0)
		// 	debug(bit1.get(tmp2));

		bit1.upd(idx1[i], d[i]+v[i]);
		bit2.upd(idx1[i], -d[i]+v[i]);
		// debug(-d[i]+v[i]);
	}
	// debug(v[3]);
	// cerr << l1 << ' ' << r1 << ' ' << l2 << ' ' << r2 << '\n';

	for (int i=0; i<n; ++i) {
		int64_t L = max(l1-d[i], d[i]-r2);
		int64_t R = min(r1-d[i], d[i]-l2);

		auto it = lower_bound(q, q+n, L);

		if (it!=q+n && *it<=R)
			return true;
	}

	return false;
}

int64_t find_shortcut(int _n, vector<int> _l, vector<int> _d, int _c) {
	c = _c;
	n = _n;

	for (int i=0; i<n; ++i)
		v[i] = _d[i];

	for (int i=0; i+1<n; ++i)
		d[i+1] = _l[i];

	for (int i=1; i<n; ++i)
		d[i] += d[i-1];

	for (int i=0; i<n; ++i)
		q[i] = d[i];
	sort(q, q+n);

	for (int i=0; i<n; ++i)
		b.push_back(-d[i]-v[i]);
	sort(b.begin(), b.end());
	b.resize(unique(b.begin(), b.end()) - b.begin());

	for (int i=0; i<n; ++i)
		idx1[i] = lower_bound(b.begin(), b.end(), -d[i]-v[i]) - b.begin() + 1;

	// PR0(v, n);

	// debug(check(1862645150));

	int64_t l = 1, r = INF;
	for (int64_t mid=(l+r)/2; mid!=l && r!=mid; mid=(l+r)/2) {
		if (check(mid))
			r = mid;
		else
			l = mid;
	}

	for (int64_t i=l; i<=r; ++i) {
		if (check(i))
			return i;
	}

	return 0;
}

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