Submission #582334

#	Time	Username	Problem	Language	Result	Execution time	Memory
582334		Josia	Friend (IOI14_friend)	C++14	46 / 100	25 ms	6052 KiB

friend

#include <bits/stdc++.h>
#include "friend.h"

using namespace std;




pair<int, int> dfs(int v, vector<vector<int>> &graph, vector<bool> &visited, vector<int> &val) {
	if (visited[v]) return {0, 0};
	visited[v] = 1;

	pair<int, int> res = {val[v], 0};

	for (int i: graph[v]) {
		pair<int, int> tmp = dfs(i, graph, visited, val);
		res.first += tmp.second;
		res.second += tmp.first;
	}

	res.first = max(res.first, res.second);
	return res;
}





// Find out best sample
int findSample(int n,int confidence[],int host[],int protocol[]){
	vector<set<int>> friends(n);
	if (n<=10) {
		for (int i = 1; i<n; i++) {
			int v = host[i];
			int type = protocol[i];
			// int value = confidence[i];

			if (type == 0) {
				for (int j = 0; j<i; j++) {
					if (j == v) {
						friends[i].insert(j);
						friends[j].insert(i);
						// friendGraph[j].push_back(i);
						// friendGraph[i].push_back(j);
						continue;
					}
				}
			}
			if (type == 1) {
				for (int j = 0; j<i; j++) {
					if (friends[v].count(j)) {
						friends[i].insert(j);
						friends[j].insert(i);
						// friendGraph[j].push_back(i);
						// friendGraph[i].push_back(j);
						continue;
					}
				}
			}
			if (type == 2) {
				for (int j = 0; j<i; j++) {
					if (friends[v].count(j) || j == v) {
						friends[i].insert(j);
						friends[j].insert(i);
						// friendGraph[j].push_back(i);
						// friendGraph[i].push_back(j);					
						continue;
					}
				}
			}
		}

		int res = 0;
		for (int i = 0; i<(1<<n); i++) {
			int tmp = 0;
			vector<int> nodes;
			for (int j = 0; j<n; j++) {
				if (i & (1<<j)) nodes.push_back(j);
			}
			bool poss = 1;
			for (int i: nodes) {
				for (int j: nodes) {
					if (friends[i].count(j)) poss = 0;
				}
			}
			if (!poss) continue;

			for (int i: nodes) {
				tmp += confidence[i];
			}
			res = max(res, tmp);

		}
		return res;
	}


	int res = 0;
	if (protocol[1] == 1) {
		for (int i = 0; i<n; i++) {
			res += confidence[i];
		}
	}
	if (protocol[1] == 2) {
		for (int i = 0; i<n; i++) {
			res = max(res, confidence[i]);
		}
	}
	if (protocol[1] == 0) {
		vector<int> val;
		for (int i = 0; i<n; i++) val.push_back(confidence[i]);
		vector<vector<int>> graph(n);

		for (int i = 1; i<n; i++) {
			graph[i].push_back(host[i]);
			graph[host[i]].push_back(i);
		}
		vector<bool> visited(n, 0);
		return dfs(0, graph, visited, val).first;
	}

	return res;

}

• Subtask 1: 11 / 11
• Subtask 2: 8 / 8
• Subtask 3: 8 / 8
• Subtask 4: 19 / 19
• Subtask 5: 0 / 23
• Subtask 6: 0 / 31