Submission #337729

#	Time	Username	Problem	Language	Result	Execution time	Memory
337729		BlancaHM	Dreaming (IOI13_dreaming)	C++14	100 / 100	116 ms	11040 KiB

dreaming

#include <iostream>
#include <vector>
#include <queue>
#include <map>
#include <unordered_map>
#include <algorithm>
#include "dreaming.h"
using namespace std;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pii;
typedef vector<pii> vpii;
typedef vector<vpii> vvpii;

pii calcDist(int i, vvpii & G, vector<bool> & visited, vi & dist1, vi & dist2, vi & dist3) {
	queue<int> Q;
	Q.push(i);
	int u, v, t, maxNode = i;
	vector<int> vertices = {};
	dist1[i] = 0;
	while(!Q.empty()) {
		u = Q.front();
		Q.pop();
		visited[u] = true;
		vertices.push_back(u);
		if (dist1[u] > dist1[maxNode])
			maxNode = u;
		for (auto connection: G[u]) {
			v = connection.first;
			t = connection.second;
			if (dist1[v] > dist1[u]+t) {
				dist1[v] = dist1[u]+t;
				Q.push(v);
			}
		}
	}
	dist2[maxNode] = 0;
	Q.push(maxNode);
	while(!Q.empty()) {
		u = Q.front();
		Q.pop();
		if (dist2[u] > dist2[maxNode])
			maxNode = u;
		for (auto connection: G[u]) {
			v = connection.first;
			t = connection.second;
			if (dist2[v] > dist2[u]+t) {
				dist2[v] = dist2[u]+t;
				Q.push(v);
			}
		}
	}
	int diam = dist2[maxNode];
	dist3[maxNode] = 0;
	Q.push(maxNode);
	while(!Q.empty()) {
		u = Q.front();
		Q.pop();
		for (auto connection: G[u]) {
			v = connection.first;
			t = connection.second;
			if (dist3[v] > dist3[u]+t) {
				dist3[v] = dist3[u]+t;
				Q.push(v);
			}
		}
	}
	int ecc = 1e9;
	for (auto vert: vertices) {
		ecc = min(ecc, max(dist2[vert], dist3[vert]));
	}
	return make_pair(ecc, diam);
}

int travelTime(int N, int M, int L, int A[], int B[], int T[]) {
	vvpii G(N, vpii());
	vector<bool> visited(N, false);
	for (int i = 0; i < M; i++) {
		G[A[i]].push_back(make_pair(B[i], T[i]));
		G[B[i]].push_back(make_pair(A[i], T[i]));
	}
	int CC = 0;
	vi diam = {}, ecc = {}, dist1, dist2, dist3;
	dist1 = dist2 = dist3 = vi(N, 1e9);
	pii curCC;
	for (int i = 0; i < N; i++) {
		if (!visited[i]) {
			curCC = calcDist(i, G, visited, dist1, dist2, dist3);
			ecc.push_back(curCC.first);
			diam.push_back(curCC.second);
			CC++;
		}
	}
	for (int i = 1; i < CC; i++) {
		if (ecc[i] > ecc[0])
			swap(ecc[0], ecc[i]);
	}
	if (CC > 1) {
		for (int i = 2; i < CC; i++) {
			if (ecc[i] > ecc[1])
				swap(ecc[i], ecc[1]);
		}
	}
	if (CC > 2) {
		for (int i = 3; i < CC; i++) {
			if (ecc[i] > ecc[2])
				swap(ecc[i], ecc[2]);
		}
	}
	int ans = 0;
	if (CC > 1) {
		ans = ecc[0]+ecc[1]+L;
		if (CC > 2)
			ans = max(ans, ecc[1]+ecc[2]+2*L);
	}
	for (int i = 0; i < CC; i++) {
		ans = max(ans, diam[i]);
	}
	return ans;
}

• Subtask 1: 14 / 14
• Subtask 2: 10 / 10
• Subtask 3: 23 / 23
• Subtask 4: 18 / 18
• Subtask 5: 12 / 12
• Subtask 6: 23 / 23