Submission #520892

#	Time	Username	Problem	Language	Result	Execution time	Memory
520892		SmolBrain	Ball Machine (BOI13_ballmachine)	C++17	100 / 100	509 ms	28340 KiB

ballmachine

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long int ll;
typedef long double ld;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define endl '\n'
#define pb push_back
#define conts continue
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define ff first
#define ss second
#define ceil2(x,y) ((x+y-1) / (y))
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#ifndef ONLINE_JUDGE
#define debug(x) cout << #x <<" = "; print(x); cout << endl
#else
#define debug(x)
#endif

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define trav(i,a) for(auto &i : a)

bool iseven(ll n) {if ((n & 1) == 0) return true; return false;}

void print(ll t) {cout << t;}
void print(int t) {cout << t;}
void print(string t) {cout << t;}
void print(char t) {cout << t;}
void print(double t) {cout << t;}
void print(ld t) {cout << t;}

template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(pair <T, V> p) {cout << "{"; print(p.ff); cout << ","; print(p.ss); cout << "}";}
template <class T> void print(vector <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(set <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(multiset <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T, class V> void print(map <T, V> v) {cout << "[ "; for (auto i : v) {print(i); cout << " ";} cout << "]";}

void usaco(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

const int MOD = 1e9 + 7;
const int maxn = 1e5 + 5;
const int inf1 = 1e9 + 5;
const ll inf2 = ll(1e18) + 5;

int curr = 1;
const int LOG = 17;
vector<vector<int>> up(maxn, vector<int>(LOG));
vector<int> adj[maxn], submn(maxn), order(maxn), depth(maxn);

void dfs1(int node, int par) {
    submn[node] = node;
    trav(child, adj[node]) {
        if (child == par) conts;

        up[child][0] = node;
        rep1(j, LOG - 1){
            up[child][j] = up[ up[child][j-1] ][j-1];
        }

        depth[child] = depth[node] + 1;

        dfs1(child, node);
        submn[node] = min(submn[node], submn[child]);
    }
}

void dfs2(int node, int par) {
    trav(child, adj[node]) {
        if (child == par) conts;
        dfs2(child, node);
    }

    order[node] = curr++;
}

void solve(int test_case)
{
    int n, q; cin >> n >> q;
    int root;

    rep1(i, n) {
        int u; cin >> u;
        if (u == 0) root = i;
        else {
            adj[i].pb(u), adj[u].pb(i);
        }
    }

    rep(j, LOG){
        up[root][j] = root;
    }

    dfs1(root, -1);

    auto comp = [&](int x, int y) {
        if (submn[x] < submn[y]) return true;
        else return false;
    };

    rep1(i, n) {
        sort(all(adj[i]), comp);
    }

    dfs2(root, -1);

    // set s stores all free nodes in the order they appear
    set<pair<int,int>> s;
    rep1(i,n){
        s.insert({order[i], i});
    }

    while(q--){
        int t; cin >> t;
        if(t == 1){
            int k; cin >> k;
            int last;

            while(k--){
                auto p = *s.begin();
                s.erase(s.begin());
                last = p.ss;
            }

            cout << last << endl;
        }
        else{
            int u; cin >> u;
            int ou = u;

            for(int j = LOG - 1; j >= 0; --j){
                int ances = up[u][j];
                pair<int,int> key = {order[ances], ances};
                if(s.count(key)) conts;

                u = up[u][j];
            }

            int ans = depth[ou] - depth[u];
            cout << ans << endl;
            s.insert({order[u], u});
        }
    }
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;
    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Compilation message (stderr)

ballmachine.cpp: In function 'void usaco(std::string)':
ballmachine.cpp:56:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ballmachine.cpp:57:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ballmachine.cpp: In function 'void solve(int)':
ballmachine.cpp:13:14: warning: 'last' may be used uninitialized in this function [-Wmaybe-uninitialized]
   13 | #define endl '\n'
      |              ^~~~
ballmachine.cpp:136:17: note: 'last' was declared here
  136 |             int last;
      |                 ^~~~
ballmachine.cpp:110:16: warning: 'root' may be used uninitialized in this function [-Wmaybe-uninitialized]
  110 |         up[root][j] = root;
      |                ^

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