Submission #959476

#	Time	Username	Problem	Language	Result	Execution time	Memory
959476		Neco_arc	Ball Machine (BOI13_ballmachine)	C++17	100 / 100	310 ms	35408 KiB

ballmachine

#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define fi(i, a, b) for(int i = a; i <= b; i++)
#define fid(i, a, b) for(int i = a; i >= b; i--)
#define maxn (int) 2e5 + 7

using namespace std;

int n, q, N;
int cl[maxn], vt[maxn], cha[maxn][18];
int Min[maxn], a[maxn];
vector<int> edges[maxn];
set<int> S;

void pre_dfs(int u, int par) {
    for(int v : edges[u]) if(v != par) {
        pre_dfs(v, u);
        Min[u] = min(Min[u], Min[v]);
    }
}

int In[maxn], Out[maxn], Time;
void dfs(int u, int par) {
    for(int v : edges[u]) if(v != par) {
        cha[v][0] = u; fi(i, 1, 17) cha[v][i] = cha[cha[v][i - 1]][i - 1];
        dfs(v, u);
    }
    a[++N] = u, vt[u] = N;
}

int Add(int k, int ans = 0) {
    while(k--) {
        ans = a[*S.begin()];
        cl[a[*S.begin()]] = 1, S.erase(S.begin());
    }
    return ans;
}

int Del(int u, int ans = 0) {
    fid(i, 17, 0) if(cl[cha[u][i]]) u = cha[u][i], ans += (1 << i);
    S.insert(vt[u]), cl[u] = 0;
    return ans;
}

int main()
{

    cin >> n >> q;

    int rt = 0;
    fi(i, 1, n) {
        Min[i] = i, S.insert(i);
        int x; cin >> x;
        if(x == 0) rt = i;
        else edges[x].push_back(i);
    }

    pre_dfs(rt, 0);
    fi(i, 1, n) sort(all(edges[i]), [](int x, int y) { return Min[x] < Min[y]; } );
    dfs(rt, 0);

    fi(i, 1, q) {
        int type, x; cin >> type >> x;
        if(type == 1) cout << Add(x) << '\n';
        else cout << Del(x) << '\n';
    }

    return 0;
}

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