Submission #1216040

#	Time	Username	Problem	Language	Result	Execution time	Memory
1216040		Lemser	Towns (IOI15_towns)	C++20	35 / 100	10 ms	328 KiB

towns

#include "towns.h"
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")
#pragma GCC target("popcnt")
using namespace std;
 
using ll = long long;
using ull = unsigned long long;
using lld = long double;
using ii = pair<int,int>;
using pll = pair<ll, ll>;
 
using vi = vector<int>;
using vll = vector<ll>;
using vii = vector<ii>;
using vpll = vector<pll>;
using vlld = vector<lld>;
 
#define all(x) x.begin(),x.end()
#define lsb(x) x&(-x)
#define gcd(a,b) __gcd(a,b)
#define sz(x) (int)x.size()
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define fls cout.flush()
 
#define fore(i, l, r) for (auto i = l; i < r; i++)
#define fo(i, n) fore (i, 0, n)
#define forex(i, r, l) for (auto i = r-1; i >= l; i--)
#define ffo(i, n) forex (i, n, 0)
 
bool cmin(ll &a, ll b) { if (b < a) { a=b; return 1; } return 0; }
bool cmax(ll &a, ll b) { if (b > a) { a=b; return 1; } return 0; }

/*
getDistance (i, j)
*/

int hubDistance(int N, int sub) {
	int A = 0, B = 0, b = 0;
	fore (i, 1, N) {
		int g = getDistance (0, i);
		if (g > b) {
			b = g; 
			A = i;
		}
	}
	vector<int> dA(N, 0), dB(N, 0);
	B = 0;
	fo (i, N) {
		if (i == A) continue;
		int g = getDistance (A, i);
		dA[i] = g;
		if (g > b) {
			b = g;
			B = i; 
		}
	}
	int ans = dA[B], ok = -1;
	fo (i, N) {
		if (i == B) continue;
		dB[i] = getDistance (B, i);
	}
	map<ll, ll> cnt;
	fo (i, N) {
		if (i == A || i == B) continue;
		int d = dA[i] + dB[i] - dA[B];
		d /= 2;
		cnt[dA[i] - d]++;
		ans = min(ans, max(dA[i], dB[i]) - d);
	}
	ll sum = 1;
	for (auto [k, v]: cnt) {
		if (max(k, dA[B] - k) > ans) {
			sum += v;
			continue;
		}
		if (v > N/2) {
			sum += v;
			continue;
		}
		if (sum <= N/2 && N - sum - v <= N/2)
			ok = 1;
		sum += v;
	}

	if (sub > 2) {
		return ans * ok;
	}
	return ans;
}

• Subtask 1: 13 / 13
• Subtask 2: 12 / 12
• Subtask 3: 0 / 13
• Subtask 4: 10 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 39