Submission #696914

#	Time	Username	Problem	Language	Result	Execution time	Memory
696914		TrungNotChung	Parkovi (COCI22_parkovi)	C++11	110 / 110	1865 ms	36108 KiB

Main

//TrungNotChung
#include <bits/stdc++.h>
#define pii pair<int , int>
#define fi first
#define se second
#define BIT(x,i) (1&((x)>>(i)))
#define MASK(x)  (1LL<<(x))
#define CNT(x) __builtin_popcountll(x)
#define task "tnc"  
 
using namespace std;
const int N = (int)2e5+228;
const long long INF = (long long)1e15;
 
int n, k, dp[N], mark[N], res[N];
vector<vector<pii> > adj;
long long dist[N], f[N];
 
void dfs(int u, int par, long long mid)
{
    mark[u] = 0, dp[u] = 0, f[u] = -INF, dist[u] = 0;
    for(int i=0; i<(int)adj[u].size(); ++i)
    {
        int v = adj[u][i].fi;
		int w = adj[u][i].se;
        if(v == par) continue;
        dfs(v, u, mid);
        f[u] = max(f[u], f[v] - w);
        dp[u] += dp[v];
        if(dist[v] == 0 && f[v] >= 0)
        {
            mark[v] = 2;
            continue;
        }
        if(dist[v] + w > mid)
        {
            mark[v] = 1;
            f[u] = max(f[u], mid - w);
            dp[u]++;
			// cout << u << " " << v << '\n';
        }
    }
	// cout << u << " " << dp[u] << '\n';
    for(int i=0; i<(int)adj[u].size(); ++i)
    {
        int v = adj[u][i].fi, w = adj[u][i].se;
        if(mark[v] || v == par) continue;
        if(f[u] - w >= dist[v])
            mark[v] = 2;
    }
    for(int i=0; i<(int)adj[u].size(); ++i)
    {
        int v = adj[u][i].fi, w = adj[u][i].se;
        if(mark[v] || v == par) continue;
        dist[u] = max(dist[u], dist[v] + w);
    }
}
 
bool check(long long mid)
{
    dfs(1, -1, mid);
	dp[1]++;
	if(dist[1] == 0 && f[1] >= 0)
		--dp[1];
    return (dp[1] <= k);
}
 
void solve()
{
    cin >> n >> k;
    adj.assign(n+7, vector<pii>());
    for(int i=1; i<n; ++i)
    {
        int u, v, w;
        cin >> u >> v >> w;
        adj[u].push_back(make_pair(v, w));
        adj[v].push_back(make_pair(u, w));
    }
    // check(29);
    // for(int i=1; i<=n; ++i)
    // {
    //     cout << dist[i] << " " << f[i] << " " << dp[i] << '\n';
    // }
    // return;
    long long l = 0, r = INF, best;
    while(l <= r)
    {
        long long mid = (l+r)/2;
        if(check(mid))
        {
            best = mid;
            for(int i=1; i<=n; ++i)
                if(mark[i] == 1) res[i] = 1;
                else res[i] = 0;
            r = mid - 1;
        }
        else l = mid + 1;
    }
    int cnt = 0;
    for(int i=1; i<=n; ++i) 
        cnt += res[i];
    cnt = k - cnt;
    for(int i=1; i<=n; ++i)
        if(res[i] == 0 && cnt > 0)
            res[i] = 1, --cnt;
    cout << best << '\n';
     for(int i=1; i<=n; ++i)
         if(res[i]) cout << i << " ";
}
 
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    solve();
    //cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
    return 0;
}
 

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 60 / 60