Submission #1022615

#	Time	Username	Problem	Language	Result	Execution time	Memory
1022615		stefanopulos	Pastiri (COI20_pastiri)	C++17	0 / 100	293 ms	43624 KiB

pastiri

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <bits/stdc++.h>
 
using namespace std;
using namespace __gnu_pbds;
 
typedef long long ll;
typedef long double ldb;
 
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<ldb,ldb> pdd;

#define ff(i,a,b) for(int i = a; i <= b; i++)
#define fb(i,b,a) for(int i = b; i >= a; i--)
#define trav(a,x) for(auto& a : x)
 
#define sz(a) (int)(a).size()
#define fi first
#define se second
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
 
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

// os.order_of_key(k) the number of elements in the os less than k
// *os.find_by_order(k)  print the k-th smallest number in os(0-based)

const int mod = 1000000007;
const int inf = 1e9 + 5;
const int mxN = 500005; 

int n, k;

vector<int> g[mxN];
bool mark[mxN];

int d[mxN];

int id[mxN];
bool cmp(int i, int j){
    return d[i] > d[j];
}

bool ok = 0;
bool bio[mxN]; 
void dfs(int v, int p, int duz){
    if(duz == 0){
        if(mark[v] && !bio[v]){
            ok = 1;
            bio[v] = 1;
        }
        return;
    }

    for(auto u : g[v]){
        if(u != p){
            dfs(u, v, duz - 1);
        }
    }

}

int main(){
    cin.tie(0)->sync_with_stdio(0);

    cin >> n >> k;
    
    vector<pii> edge;
    ff(i,1,n - 1){
        int u, v;
        cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
        edge.pb({u, v});
    }

    ff(i,1,k){
        int X;
        cin >> X;
        mark[X] = 1;
    }

    ff(i,1,n)d[i] = inf;

    queue<int> que;
    ff(i,1,n){
        if(mark[i] == 1){
            que.push(i);
            d[i] = 0;
        }
    }

    while(sz(que)){
        int v = que.front(); que.pop();
        for(auto u : g[v]){
            if(d[u] == inf){
                d[u] = d[v] + 1;
                que.push(u);
            }
        }
    }

    ff(i,1,n)id[i] = i;
    sort(id + 1, id + n + 1, cmp);

    vector<int> res;
    ff(i,1,n){
        int u = id[i];

        int br = 0;
        for(auto c : g[u])br += (d[c] == d[u] - 1);

        if(br == 1)continue;

        ok = 0; dfs(u, -1, d[u]);
        if(ok == 1){
            res.pb(u);
        }

    }

    cout << sz(res) << '\n';
    for(auto c : res)cout << c << " ";
    cout << '\n';

    return 0;
}
/*

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1 3 9 11 12 15 16 19 20


// probati bojenje sahovski
*/
 
 
 
 
 

• Subtask 1: 0 / 8
• Subtask 2: 0 / 18
• Subtask 3: 0 / 23
• Subtask 4: 0 / 51