Submission #386598

#	Time	Username	Problem	Language	Result	Execution time	Memory
386598		milleniumEeee	Biochips (IZhO12_biochips)	C++17	0 / 100	10 ms	10112 KiB

biochips

#include <bits/stdc++.h>
#define fastInp ios_base::sync_with_stdio(0); cin.tie(0);
#define fr first
#define sc second
#define pii pair<int, int>
#define pb push_back
#define all(s) s.begin(), s.end()
#define szof(s) (int)s.size()
using namespace std;

const int MAXN = (int)2e5 + 5;

vector <int> g[MAXN];
int cost[MAXN];

int tin[MAXN], tout[MAXN], tiktak = 0;

void precalc(int v, int par) {
	tin[v] = ++tiktak;
	for (int to : g[v]) {
		if (to != par) {
			precalc(to, v);
		}
	}	
	tout[v] = tiktak;
}

bool father(int a, int b) {
	return (tin[a] <= tin[b] && tout[b] <= tout[a]);
}

signed main() {
	fastInp;
	int n, m;
	cin >> n >> m;
	assert(n <= 20); // wtf
	int root = -1;
	for (int i = 1; i <= n; i++) {
		int par, x;
		cin >> par >> x;
		if (!par) {
			root = i;
		} else {
			g[par].pb(i);
			g[i].pb(par);
		}
		cost[i] = x;
	}
	precalc(root, -1);
	int ans = 0;
	for (int mask = 0; mask < (1 << n); mask++) {
		int cnt = __builtin_popcount(mask);
		if (cnt != m) {
			continue;
		}
		vector <int> vec;
		for (int i = 0; i < n; i++) {
			if (mask & (1 << i)) {
				vec.pb(i + 1);
			}
		}
		bool ok = 1;
		for (int i = 0; i < m; i++) {
			for (int j = 0; j < m; j++) {
				if (i == j) {
					continue;
				}
				ok &= (!father(vec[i], vec[j]));
			}
		}
		if (ok) {
			int sum = 0;
			for (int el : vec) {
				sum += cost[el];
			}	
			ans = max(ans, sum);
		}
	}
	cout << ans << endl;
}

• Subtask 1: 0 / 100