Submission #447657

#	Time	Username	Problem	Language	Result	Execution time	Memory
447657		prvocislo	Ball Machine (BOI13_ballmachine)	C++17	100 / 100	228 ms	26668 KiB

ballmachine

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

const int maxn = 1e5 + 5, logn = 17;
int l[logn][maxn], mini[maxn], inv[maxn], n, q;
vector<pair<int, int> > g[maxn];
vector<int> ord;
void dfs1(int u, int p = -1)
{
    for (int i = 1; i < logn; i++) if (l[i-1][u] != -1) l[i][u] = l[i-1][l[i-1][u]];
    for (pair<int, int> &v : g[u]) if (v.first != p) 
    {
        l[0][v.first] = u;
        dfs1(v.first, u);
        v.second = mini[v.first];
        mini[u] = min(mini[u], mini[v.first]);
    }
}
void dfs2(int u, int p = -1)
{
    for (pair<int, int> &v : g[u]) if (v.first != p) 
        dfs2(v.first, u);
    inv[u] = ord.size(), ord.push_back(u);
}
bool cmp(pair<int, int> a, pair<int, int> b) { return a.second < b.second; }
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> q;
    iota(mini, mini+n, 0);
    int root = -1;
    for (int i = 0, p; i < n; i++)
    {
        cin >> p; p--;
        if (p == -1) root = i;
        else g[p].push_back({i, -1});
    }
    for (int i = 0; i < logn; i++) for (int j = 0; j < n; j++) l[i][j] = -1;
    dfs1(root); 
    for (int i = 0; i < n; i++) sort(g[i].begin(), g[i].end(), cmp);
    dfs2(root);
    set<int> s;
    for (int i = 0; i < n; i++) s.insert(i);
    vector<bool> b(n, false);
    while (q--)
    {
        int typ; cin >> typ;
        if (typ == 1)
        {
           int k; cin >> k;
           int ans = -1;
           for (int i = 0; i < k; i++)
           {
                int vr = ord[*s.begin()];
                ans = vr;
                b[vr] = true;
                s.erase(s.begin());
           }
           cout << ans+1 << "\n";
        }
        else
        {
            int x; cin >> x; x--;
            int y = x, ans = 0;
            for (int i = logn-1; i >= 0; i--) if (l[i][y] != -1 && b[l[i][y]]) y = l[i][y], ans += (1 << i);
            b[y] = false; s.insert(inv[y]);
            cout << ans << "\n";
        }
    }
    return 0;
}

• Subtask 1: 25 / 25
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40
• Subtask 4: 5 / 5