Submission #363572

#	Time	Username	Problem	Language	Result	Execution time	Memory
363572		silverfish	Friend (IOI14_friend)	C++14	8 / 100	1 ms	492 KiB

friend

#include "friend.h"
#include <bits/stdc++.h>
using namespace std;

const int N = 1e3;

vector<int> adj[N];
long long dp[N][2];
int vis[N], side[N], friends[N];

void dfs(int u, int p, int *conf){

	for(int v : adj[u]){
		if(v != p) dfs(v, u, conf);
	}

	for(int v : adj[u]){
		if(v != p){
			dp[u][0] += max(dp[v][1], dp[v][0]);
			dp[u][1] += dp[v][0];
		}
	}
	dp[u][1] += 1LL*conf[u];
}

int findSample(int n, int conf[],int host[],int protocol[]){
	bool subtask2 = 1, subtask3 = 1, subtask4 = 1, subtask5 = 1;
	if(conf[0] != 1) subtask5 = 0;
	for(int i = 1; i < n; ++i){
		if(protocol[i] != 1) subtask2 = 0;
		if(protocol[i] != 2) subtask3 = 0;
		if(protocol[i] != 0) subtask4 = 0;
		if(conf[i] != 1) subtask5 = 0;
	}
	if(subtask5){
		side[0] = 0;
		array<long long,2> ans = {0, 0};
		++ans[side[0]];
		friends[0] = 0;
		for(int i = 1; i < n; ++i){
			if(protocol[i] == 0){
				side[i] = !side[host[i]];
				++ans[side[i]];
				friends[i] = 1;
				++friends[host[i]];
			}else{
				side[i] = side[host[i]];
				friends[i] = friends[host[i]];

				if(friends[i] == 0) ++ans[!side[i]];
				++ans[side[i]];
			}
		}
		if(friends[0] == 0) ++ans[!side[0]];
		return max(ans[0], ans[1]);
	}
	if(subtask2){
		long long ans = 0;
		for(int i = 0; i < n; ++i) ans += 1LL*conf[i];
		return ans;
	}
	if(subtask3){
		assert(0);
		return *max_element(conf, conf+n);
	}

	if(subtask4){
		assert(0);
		//build tree
		for(int i = 1; i < n; ++i){
			adj[host[i]].push_back(i);
			adj[i].push_back(host[i]);
		}

		dfs(0, 0, conf);
		return max(dp[0][1], dp[0][0]);
	}


	return -1;
}

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