Submission #869671

#	Time	Username	Problem	Language	Result	Execution time	Memory
869671		12345678	Ball Machine (BOI13_ballmachine)	C++17	100 / 100	279 ms	32848 KiB

ballmachine

#include <bits/stdc++.h>

using namespace std;

const int nx=1e5+5, kx=17;
int n, q, x, pa[nx][kx], mn[nx], t, id[nx], rid[nx], c, lvl[nx], rt;
vector<int> d[nx];

struct segtree
{
    int d[4*nx], lz[4*nx];
    void pushlz(int l, int r, int i)
    {
        if (!lz[i]) return;
        lz[i]=0;
        d[i]=r-l+1;
        if (l==r) return;
        lz[2*i]=lz[2*i+1]=1;
    }
    void update(int l, int r, int i, int ql, int qr)
    {
        pushlz(l, r, i);
        if (qr<l||r<ql) return;
        if (ql<=l&&r<=qr) return lz[i]=1, pushlz(l, r, i), void();
        int md=(l+r)/2;
        update(l, md, 2*i, ql, qr);
        update(md+1, r, 2*i+1, ql, qr);
        d[i]=d[2*i]+d[2*i+1];
    }
    void update2(int l, int r, int i, int idx)
    {
        pushlz(l, r, i);
        if (r<idx||idx<l) return;
        if (l==r) return void(d[i]=0);
        int md=(l+r)/2;
        update2(l, md, 2*i, idx);
        update2(md+1, r, 2*i+1, idx);
        d[i]=d[2*i]+d[2*i+1];
    }
    int query(int l, int r, int i, int key)
    {
        pushlz(l, r, i);
        if (l==r) return l;
        int md=(l+r)/2;
        if (md-l+1-d[2*i]>=key) return query(l, md, 2*i, key);
        else return query(md+1, r, 2*i+1, key-(md-l+1-d[2*i]));
    }
    bool query2(int l, int r, int i, int idx)
    {
        pushlz(l, r, i);
        if (idx<l||r<idx) return 0;
        if (l==r) return d[i]==1;
        int md=(l+r)/2;
        return query2(l, md, 2*i, idx)||query2(md+1, r, 2*i+1, idx);
    }
} s;

void dfs(int u, int p)
{
    pa[u][0]=p; lvl[u]=lvl[p]+1;
    mn[u]=u;
    for (int i=1; i<kx; i++) pa[u][i]=pa[pa[u][i-1]][i-1];
    for (auto v:d[u]) dfs(v, u), mn[u]=min(mn[u], mn[v]);
}

void dfs2(int u)
{
    vector<pair<int, int>> tmp;
    for (auto v:d[u]) tmp.push_back({mn[v], v});
    sort(tmp.begin(), tmp.end());
    for (auto [x, y]:tmp) dfs2(y);
    id[u]=++t;
    rid[t]=u;
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n>>q;
    for (int i=1; i<=n; i++) 
    {
        cin>>x;
        if (x!=0) d[x].push_back(i);
        else rt=i;
    }
    dfs(rt, rt); dfs2(rt);
    while (q--)
    {
        cin>>t>>x;
        if (t==1) 
        {
            x=s.query(1, n, 1, x);
            s.update(1, n, 1, 1, x);
            cout<<rid[x]<<'\n';
        }
        else
        {
            int sv=x;
            for (int i=kx-1; i>=0; i--) if (s.query2(1, n, 1, id[pa[x][i]])==1) x=pa[x][i];
            s.update2(1, n, 1, id[x]);
            cout<<lvl[sv]-lvl[x]<<'\n';
        }
    }
}

/*
8 9
0
1
2
2
3
3
4
6
1 8
2 5
2 7
2 8
1 3
2 8
2 8
2 8
2 8
*/

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