Submission #697644

#	Time	Username	Problem	Language	Result	Execution time	Memory
697644		Do_you_copy	Ball Machine (BOI13_ballmachine)	C++17	100 / 100	384 ms	28216 KiB

ballmachine

//Then
#include <bits/stdc++.h>
#define pb push_back
#define fi first
#define se second
#define faster ios_base::sync_with_stdio(0); cin.tie(0);

using namespace std;
using ll = long long;
using ld = long double;
using pii = pair <int, int>;
mt19937_64 Rand(chrono::steady_clock::now().time_since_epoch().count());
const int maxN = 1e5 + 1;
//const int Mod = 1e9 + 7;
//const int inf =
int n, q, root;
vector <int> adj[maxN];
int lift[maxN][20];
int depth[maxN];
int dp[maxN];
int tout[maxN], rtout[maxN], timedfs;

void pre_dfs(int u, int p){
    lift[u][0] = p;
    depth[u] = depth[p] + 1;
    dp[u] = u;
    for (int i = 1; i < 20; ++i){
        lift[u][i] = lift[lift[u][i - 1]][i - 1];
    }
    for (int i: adj[u]){
        pre_dfs(i, u);
        dp[u] = min(dp[u], dp[i]);
    }
}

void dfs(int u){
    sort(adj[u].begin(), adj[u].end(),[&](const int &i, const int &j){
        return dp[i] < dp[j];
    });
    for (int i: adj[u]){
        dfs(i);
    }
    tout[u] = ++timedfs;
    rtout[tout[u]] = u;
}

void Init(){
    cin >> n >> q;
    for (int i = 1; i <= n; ++i){
        int x; cin >> x;
        if (x == 0){
            root = i;
        }
        else{
            adj[x].pb(i);
        }
    }
    pre_dfs(root, 0);
    dfs(root);
    tout[0] = n + 1;
    rtout[n + 1] = 0;
    set <int> S;
    for (int i = 1; i <= n + 1; ++i) S.insert(i);
    while (q--){
        int t, x;
        cin >> t >> x;
        if (t == 1){
            int last = 0;
            while (x){
                --x;
                last = *S.begin();
                S.erase(*S.begin());
            }
            cout << rtout[last] << "\n";
        }
        else{
            int u = x;
            for (int i = 18; i >= 0; --i){
                if (S.find(tout[lift[u][i]]) == S.end()){
                    u = lift[u][i];
                }
            }
            cout << depth[x] - depth[u] << "\n";
            S.insert(tout[u]);
        }
    }
}

#define debug
#define taskname "test"
signed main(){
    faster
    if (fopen(taskname".inp", "r")){
        freopen(taskname".inp", "r", stdin);
        freopen(taskname".out", "w", stdout);
    }
    int tt = 1;
    //cin >> tt;
    while (tt--){
        Init();
    }
    if (fopen("timeout.txt", "r")){
        ofstream timeout("timeout.txt");
        timeout << signed(double(clock()) / CLOCKS_PER_SEC * 1000);
        timeout.close();
        #ifndef debug
        cerr << "Time elapsed: " << signed(double(clock()) / CLOCKS_PER_SEC * 1000) << "ms\n";
        #endif // debug
    }
}

Compilation message (stderr)

ballmachine.cpp: In function 'int main()':
ballmachine.cpp:94:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |         freopen(taskname".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
ballmachine.cpp:95:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   95 |         freopen(taskname".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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