Submission #1028397

#	Time	Username	Problem	Language	Result	Execution time	Memory
1028397		Dan4Life	Towns (IOI15_towns)	C++17	25 / 100	10 ms	1116 KiB

towns

#include "towns.h"
#include <bits/stdc++.h>
using namespace std;
#define sz(a) (int)a.size()
using ar2 = array<int,2>;
const int mxN = 115;
int n, mem[mxN][mxN];
map<int,int> M, cnt;
 
int dis(int a, int b){
	if(a==b) return 0;
	if(mem[a][b]!=-1) return mem[a][b];
	if(mem[b][a]!=-1) return mem[b][a];
	return mem[a][b]=mem[b][a]=getDistance(a,b);
}
 
int p[mxN], sz[mxN];
int findSet(int i) { return p[i]==i?i:p[i]=findSet(p[i]); }
bool isSameSet(int i, int j) { return findSet(i)==findSet(j); }
 
void unionSet(int i, int j){
	int x = findSet(i), y = findSet(j);
	if(x==y) return;
	if(sz[x]<sz[y]) swap(x,y);
	p[y]=x; sz[x]+=sz[y];
}

int a, b, diameter; 
bool same(int i, int j, int lpos){
	int rpos = diameter-lpos;
	int i_u = dis(a,i)-lpos;
	if(dis(a,i)<dis(b,i)) i_u = dis(b,i)-rpos;
	int u_j = dis(a,j)-lpos;
	if(dis(a,j)<dis(b,j)) u_j = dis(b,j)-rpos;
	return i_u+u_j != dis(i,j);
}

int hubDistance(int N, int sub) {
	n = N; ar2 mx = {0,0}; 
	M.clear(); cnt.clear();
	memset(mem,-1,sizeof(mem));
	for(int i = 0; i < n; i++) 
		mx=max(mx,{dis(0,i),i});
	a = mx[1]; mx = {0,0};
	for(int i = 0; i < n; i++)
		mx=max(mx,{dis(a,i),i});
	b = mx[1]; diameter = mx[0];
	int ans = diameter;
	
	for(int i = 0; i < n; i++){
		int i_0 = (dis(0,i)+dis(0,a)-dis(a,i))/2;
		int lpos = dis(0,a) - i_0; 
		int rpos = diameter-lpos;
		M[i_0] = max(lpos, rpos);
		cnt[i_0]++;
	}
	for(auto u : M) ans=min(ans, u.second);
	if(sub<=2) return ans;
	
	int tot = 0;
	for(auto u : M){
		int pos = u.first, mx_dis = u.second;
		tot+=cnt[pos];
		if(mx_dis!=ans) continue;
		if(tot-cnt[pos] > n/2) continue;
		if(n-tot > n/2) continue;
		return ans;
	}
	return -ans;
}

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