Submission #16580

#	Time	Username	Problem	Language	Result	Execution time	Memory
16580		gs14004	Towns (IOI15_towns)	C++14	35 / 100	28 ms	1720 KiB

towns

#include "towns.h"
#include <cstring>
#include <algorithm>
#include <stack>
#include <vector>
using namespace std;
typedef pair<int,int> pi;

int dp[150][150];

int dist(int s, int e){
	if(s == e) return 0;
	if(s > e) swap(s,e);
	if(~dp[s][e]) return dp[s][e];
	return dp[s][e] = getDistance(s, e);
}

vector<pi> v;

int p, q, val;
bool diff(int s, int e){
	return (val + dist(s, e)) == dist(s, p) + dist(q, e);
}

stack<int> stk;
int st;
int solve(int s, int e){
	if(st == 2) return 0;
	if(st == 4) return e - s + 1;
	while(!stk.empty()) stk.pop();
	for(int i=s; i<=e; i++){
		if(stk.empty()){
			stk.push(v[i].second);
		}
		else if(diff(stk.top(), v[i].second)){
			stk.pop();
		}
		else{
			stk.push(v[i].second);
		}
	}
	if(stk.empty()) return 0;
	int cnt = 0;
	for(int i=s; i<=e; i++){
		if(!diff(stk.top(), i)) cnt++;
	}
	return cnt;
}

int hubDistance(int N, int sub) {
	st = sub;
	v.clear();
	memset(dp,-1,sizeof(dp));
	p = -1, val = -1, q = -1;
	for(int i=1; i<N; i++){
		if(val < dist(0, i)){
			val = dist(0, i);
			p = i;
		}
	}
	val = -1;
	for(int i=0; i<N; i++){
		if(val < dist(p, i)){
			val = dist(p, i);
			q = i;
		}
	}
	for(int i=0; i<N; i++){
		int fl = dist(p, i) - dist(q, i) + val;
		v.push_back(pi(fl / 2, i));
	}
	sort(v.begin(), v.end());
	int R = val;
	int hmin = 1e9;
	for(int i=0; i<v.size(); ){
		int e = i;
		while(e < v.size() && v[e].first == v[i].first) e++;
		int tmp = max(val - v[i].first, v[i].first);
		if(R > tmp){
			R = tmp;
			hmin = 1e9;
		}
		if(R == tmp){
			int hub = max(solve(i, e-1), max(i, (int)v.size() - e));
			hmin = min(hmin, hub);
		}
		i = e;
	}
	if(hmin > N / 2) return -R;
	return R;
}

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