Submission #684988

#	Time	Username	Problem	Language	Result	Execution time	Memory
684988		saayan007	Biochips (IZhO12_biochips)	C++14	10 / 100	95 ms	16404 KiB

biochips

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

using ll = long long;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using vi = vector<int>;
using vl = vector<ll>;
using vpi = vector<pi>;
using vpl = vector<pl>;

#define fur(i, a, b) for(ll i = a; i <= (ll)b; ++i)
#define ruf(i, a, b) for(ll i = a; i >= (ll)b; --i)
#define fr first 
#define sc second
#define mp make_pair
#define pb push_back
#define nl "\n"
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()

const ll mxn = 200001;
const ll inf = 1e10L;
ll n, m;
ll root;
ll p[mxn + 1];
vl adj[mxn + 1];
ll s[mxn + 1];

ll dfs(ll cur, ll src, ll bit, bool ch) {
    ll ans = 0;
    if(bit & (1 << cur)) {
        if(!ch)
            return -inf;
        ans += s[cur];
        ch = 0;
    }

    for(auto u : adj[cur]) {
        if(u != src) {
            ll add = dfs(u, cur, bit, ch);
            if(add < 0)
                return -inf;
            ans += add;
        }
    }
    return ans;
}

int main() 
{
    ios::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> m;
    fur(i, 0, n - 1) {
        cin >> p[i] >> s[i];

        --p[i];

        if(p[i] != -1) {
            adj[i].pb(p[i]);
            adj[p[i]].pb(i);
        } else {
            root = i;
        }
    }

    ll res = -inf;
    fur(i, 0, (1 << n) - 1) {
        if(__builtin_popcountll(i) != m) {
            continue;
        }

        res = max(res, dfs(root, -1, i, 1));
    }
    cout << res << nl;
}

• Subtask 1: 10 / 100