Submission #105981

#	Time	Username	Problem	Language	Result	Execution time	Memory
105981		TuGSGeReL	Friend (IOI14_friend)	C++14	19 / 100	35 ms	2804 KiB

friend

#include "friend.h"
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
 
using namespace std;
using namespace __gnu_pbds;
 
#define ll long long
#define mp make_pair
#define pub push_back
#define pob pop_back()
#define ss second
#define ff first
#define mt make_tuple
#define pof pop_front()
#define fbo find_by_order
#define ook order_of_key
 
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
using pll = pair <ll, ll>;
using pii = pair <int, int>;
 
int used[2001], pre[3], dp[2001][2], par[2001], fl[2001][2001], st[2001];
vector <int> edg[2001], to[2001];
 
int solve1(int n, int confidence[], int host[], int protocol[])
{
 
	int ans = 0;

	for (int i = 1; i < n; i++)
	{
    	if ( !protocol[i] )
    	{
    		edg[i].pub(host[i]);
			edg[host[i]].pub(i);
    	} else if ( protocol[i] == 1 )
    	{
    		for (int j = 0; j < edg[host[i]].size(); j++)
    		{
    			edg[edg[host[i]][j]].pub(i);
    			edg[i].pub(edg[host[i]][j]);
    		}
    	} else {
    		
			for (int j = 0; j < edg[host[i]].size(); j++)
    		{
    			edg[i].pub(edg[host[i]][j]);
				edg[edg[host[i]][j]].pub(i);
    		}
 	
			edg[i].pub(host[i]);
			edg[host[i]].pub(i);
		}
	}
 
	for (int i = 0; i < (1 << n); i++)
	{
		memset(used, 0, sizeof used);
		bool boo = 0;
		int res = 0;
 
		for (int j = 0; j < n; j++)
		{
    		if ( i & (1 << j) )
    		{
    			for ( auto x : edg[j] )
        			if ( used[x] )
            			boo = 1;
 
        	res += confidence[j];
        	used[j] = 1;
			}
		}

		if ( !boo )
			ans = max(ans, res);
	}
 
	return ans;
}
 
void dfs(int u, int pra)
{
	for (auto x : edg[u])
		if ( x != pra )
    		dfs(x, u);
 
	if ( pra != -1 )
	{
		dp[pra][0] += max(dp[u][1], dp[u][0]);
		dp[pra][1] += dp[u][0];
	}
}
 
bool bfs(int u, int n)
{
	memset(used, 0, sizeof used);
	used[u] = 1;
	par[u] = -1;
	queue<int>q;
	q.push(u);
	
	while (!q.empty())
	{
		u = q.front();
		q.pop();
		
		for (auto x : to[u])
		{
			if ( !used[x] && fl[u][x] )
			{
				used[x] = 1;
				par[x] = u;
				q.push(x);
			}
		}
	}
 
	if ( used[n] )
		return 1;
 
	return 0;
}
 
int findSample(int n,int confidence[],int host[],int protocol[])
{
	if ( protocol[1] )
	{
		int x = -1;
		return confidence[x];
	}

	if ( n <= 10 )
		return solve1(n, confidence, host, protocol);

	for (int i = 1; i < n; i++)
		pre[protocol[i]]++;

	if ( pre[1] == n - 1 )
	{
    	int ans = 0;
 
		for (int i = 0; i < n; i++)
    		ans += confidence[i];

		return ans;
	}

	if ( pre[2] == n - 1 )
	{
		int ans = 0;
 
		for (int i = 0; i < n; i++)
		ans = max(ans, confidence[i]);
 
		return ans;
	}

	if ( pre[0] == n - 1 )
	{
		for (int i = 1; i < n; i++)
		{
    		edg[host[i]].pub(i);
    		edg[i].pub(host[i]);
    	}

    	for (int i = 0; i < n; i++)
			dp[i][1] = confidence[i];

		dfs(0, -1);

	    return max(dp[0][0], dp[0][1]);
	}
	
	for (int i = 1; i < n; i++)
	{
		if ( !protocol[i] )
		{
			st[i] = 1 ^ st[host[i]];
			edg[i].pub(host[i]);
    		edg[host[i]].pub(i);
    		if ( st[i] )
				fl[host[i]][i] = 1, to[host[i]].pub(i);
			else 
				fl[i][host[i]] = 1, to[i].pub(host[i]);
		} else {
			for (auto x : edg[host[i]])
    		{
    			st[i] = st[x] ^ 1;
    			edg[x].pub(i);
    			edg[i].pub(x);
    			if ( st[i] )
    				fl[x][i] = 1, to[x].pub(i);
    			else
    				fl[i][x] = 1, to[i].pub(x);
			}
    	}
	}
	
	for (int i = 0; i < n; i++)
	{
		if ( st[i] )
			fl[i][n] = 1, to[i].pub(n);
		else
			fl[n + 1][i] = 1, to[n + 1].pub(i);
	}
	
	int ans = 0;
 
	while ( bfs(n + 1, n) )
	{
		int mn = 1e9;
		
		for (int i = n; par[i] != -1; i = par[i])
    		mn = min(mn, fl[par[i]][i]);
		
    	for (int i = n; par[i] != -1; i = par[i])
    		fl[par[i]][i] -= mn, fl[i][par[i]] += mn;
		
		ans += mn;
	}

	return n - ans;
}
/*
10
1 1 1 1 1 1 1 1 1 1 
0 0
0 0
1 0
1 1
0 1
4 0
3 0
2 1
5 0
*/
/*
5
1 1 1 1 1 
0 1
1 1
2 0
1 0
*/

Compilation message (stderr)

friend.cpp: In function 'int solve1(int, int*, int*, int*)':
friend.cpp:39:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
       for (int j = 0; j < edg[host[i]].size(); j++)
                       ~~^~~~~~~~~~~~~~~~~~~~~
friend.cpp:46:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int j = 0; j < edg[host[i]].size(); j++)
                    ~~^~~~~~~~~~~~~~~~~~~~~
friend.cpp: In function 'int findSample(int, int*, int*, int*)':
friend.cpp:218:6: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
      for (int i = n; par[i] != -1; i = par[i])
      ^~~
friend.cpp:221:3: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   ans += mn;
   ^~~

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