Submission #134749

#	Time	Username	Problem	Language	Result	Execution time	Memory
134749		nvmdava	Towns (IOI15_towns)	C++17	23 / 100	22 ms	380 KiB

towns

#include "towns.h"
#include <bits/stdc++.h>
#define ff first
#define ss second
using namespace std;
int d[2][200], v = 0;
map<int, int> cntr;
int hubDistance(int N, int sub) {
	memset(d, 0,sizeof d);
	cntr.clear();
	for(int i = 0 ; i < N; i++)
		if(d[0][v] < (d[0][i] = getDistance(0, i)))
			v = i;

	int D = 0;
	int T = d[0][v];
	
	for(int i = 0; i < N; i++)
		D = max(D, d[1][i] = getDistance(v, i));


	int r = 1000000000;
	for(int i = 0; i < N; i++){
		int s = (T - d[0][i] + d[1][i]) >> 1;
		cntr[s]++;
		r = min(r, max(s, D - s));
	}
	int chk = -1;
	int l = 0;
	for(auto& x : cntr){
		if(l <= N / 2){
			l += x.ss;
			if(N - l <= N / 2){
				if(max(D - x.ff, x.ff) == r){
					if(x.ss <= N / 2) return r;
					chk = x.ff << 1;
				}
			}
		}
	}
	if(chk == -1) return -r;
	vector<int> s, t, o;
	for(int i = 0; i < N; i++)
		if(T + d[1][i] - d[0][i] == chk)
			s.push_back(i);
	o = s;
	while(s.size() > 1){
		for(int i = 1; i < s.size(); i += 2)
			if(getDistance(s[i], s[i - 1]) != d[0][s[i]] + d[1][s[i - 1]] - T)
				t.push_back(s[i]);
		if(s.size() & 1)
			t.push_back(s.back());
		swap(s, t);
		t.clear();
	}

	if(s.size() == 0) return r;

	int sz = 0;
	for(int& x : o)
		if(getDistance(s[0], x) != d[0][x] + d[1][s[0]] - T)
			sz++;
	if(sz > N / 2) return -r;
	return r;
}

Compilation message (stderr)

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:48:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 1; i < s.size(); i += 2)
                  ~~^~~~~~~~~~
towns.cpp:8:28: warning: unused parameter 'sub' [-Wunused-parameter]
 int hubDistance(int N, int sub) {
                            ^~~

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