Submission #40802

#	Time	Username	Problem	Language	Result	Execution time	Memory
40802		ssnsarang2023	Gap (APIO16_gap)	C++14	30 / 100	94 ms	2160 KiB

gap

#include <bits/stdc++.h>
#include "gap.h"
 
using namespace std;
 
typedef long long ll;
 
//#define DEBUG
 
#ifdef DEBUG
 
int n = 5;
ll a[5] = {2, 3, 6, 8, 12};
 
void MinMax(ll x, ll y, ll *mn, ll *mx) {
	for (int i = 0; i < n; ++i) if (a[i] >= x)
	{ (*mn) = a[i]; break; }
	for (int i = n - 1; i >= 0; --i) if (a[i] <= y)
	{ (*mx) = a[i]; break; }
	if ((*mx) < (*mn)) (*mx) = (*mn) = -1;
}
#endif
 
ll findGap(int _t, int _n) {
	ll n = _n;
	ll mn = 1, mx = (ll)1e18;
	MinMax(mn, mx, &mn, &mx);
	if (_t == 2) {
		ll d = (mx - mn) / (n - 1ll) + (ll)((mx - mn) % (n - 1ll) != 0ll), pre = mn;
		ll pstep = mn, step = mn + d - 1, gap = 0;
		while (1) {
			ll mntmp = -1, mxtmp = -1;
			MinMax(pstep + 1ll, step, &mntmp, &mxtmp);
			if (step >= mx - 1ll) {
				if (mxtmp != -1ll) gap = max(gap, mx - mxtmp);
				else gap = max(gap, mx - pre);
				break;
			} else if (mntmp != -1ll) gap = max(gap, mntmp - pre);
			pre = max(pre, mxtmp), pstep = step, step += d;
		}
		return gap;
	} else {
		vector<ll> a;
		a.resize(n);
		a[0] = mn, a[n - 1] = mx;
		int lo = 0, hi = n - 1;
		while (hi - lo > 1) {
			MinMax(a[lo] + 1ll, a[hi] - 1ll, &mn, &mx);
			++lo, --hi;
			a[lo] = mn, a[hi] = mx;
		}
		ll gap = 0;
		for (int i = 0; i < n - 1; ++i) gap = max(gap, a[i + 1] - a[i]);
		return gap;
	}
	return 0ll;
}
 
#ifdef DEBUG
int main() {
	printf("%d", findGap(1, 5));
	return 0;
}
#endif

• Subtask 1: 30 / 30
• Subtask 2: 0 / 70