Submission #383865

#	Time	Username	Problem	Language	Result	Execution time	Memory
383865		LucaDantas	Towns (IOI15_towns)	C++17	25 / 100	19 ms	1280 KiB

towns

#include "towns.h"
#include <cstring>
#include <cstdio>
#include <algorithm>
#include <cassert>
#include <vector>
#include <map>
 
constexpr int maxn = 300;
 
int dp[maxn][maxn];//, c[maxn];
 
std::map<int, int> filhos;
// std::map<int, std::vector<int>> filhos;
 
int get(int i, int j) {
	if(i > j) std::swap(i, j);
	return dp[i][j] != -1 ? dp[i][j] : dp[i][j] = getDistance(i, j);
}
 
int max(int a, int b) { return a > b ? a : b; }
int min(int a, int b) { return a < b ? a : b; }
 
int hubDistance(int N, int sub) {
	memset(dp, -1, sizeof dp);
	// memset(c, 0, sizeof c);
	filhos.clear();
	int a = 0, b = 0, dist = 0;
	for(int i = 0; i < 2; i++) {
		for(int j = 0; j < N; j++) {
			if(a != j) {
				int v = get(a, j);
				if(v > dist) b = j, dist = v;
			}
		}
		if(!i) a = b, dist = 0, b = 0;
	}
	int R = 0x3f3f3f3f;
	for(int i = 0; i < N; i++) {
		if(i == a || i == b) continue;
		int d1 = get(a, i), d2 = get(b, i);
		int c = (d1 + d2 - dist) >> 1;
		// c[i] = (d1 + d2 - dist) >> 1;
		R = min(R, max(d1, d2) - c);
		// R = min(R, max(d1, d2) - c[i]);
		filhos[d1]++;
	}
	if(sub <= 2) return R;
	if(sub != 4) assert(0);
	int sz = 1;
	bool ok = 0;
	for(auto it : filhos) {
		if(it.first != R && it.first != dist - R) {
			sz += it.second;
			continue;
		}
		if(sz > (N >> 1) || N - sz - it.second > (N >> 1)
			|| it.second > (N >> 1)) continue;
		sz += it.second;
		ok = 1;
	}
	return R * (ok?1:-1);
}

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