Submission #1083481

#	Time	Username	Problem	Language	Result	Execution time	Memory
1083481		SamueleVid	Beech Tree (IOI23_beechtree)	C++17	14 / 100	58 ms	13208 KiB

beechtree

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

constexpr int MAXN = 2e5 + 5;
constexpr int MAXM = 2e5 + 5;
vector<int> P, C;
vector<int> curr;
vector<int> permutato;
vector<bool> v;
vector<int> adj[MAXN];
int colori_usati[MAXM];
bool sol[MAXN];

void vediamo(int u) {
    // cout << "vediamo " << u << '\n';
    // colori_usati[C[u]] ++;

    vector<int> to_remove;

    // cout << "colori_usati : ";
    // for (int i = 0; i < 4; i ++) cout << colori_usati[i] << " ";
    // cout << '\n';

    // cout << "permutazione da verificare per " << u << " : ";
    // for (auto x : permutato) cout << x << " ";
    // cout << '\n';



    for (int i = 1; i < permutato.size(); i ++) {
        int f_i = colori_usati[C[permutato[i]]];
        // cout << "permutato[i], f_i : " << permutato[i] << " " << f_i << '\n';
        if (P[permutato[i]] != permutato[f_i]) {
            for (auto x : to_remove) colori_usati[x] --;
            return;
        }
        to_remove.push_back(C[permutato[i]]);
        colori_usati[C[permutato[i]]] ++;
    }
    
    // cout << "permutazione valida per " << u << " : ";
    // for (auto x : permutato) cout << x << " ";
    // cout << '\n';


    // cout << "sol[u] = 1 !!" << '\n';
    
    for (auto x : to_remove) colori_usati[x] --;

    sol[u] = 1;

    // for (int i = 0; i < 4; i ++) cout << sol[i] << " ";
    // cout << '\n';
}

void generate_permutation(int u, int i) {
    // cout << "permutazione u : " << u << " i : " << i << '\n';
    if (sol[u]) return;
    if (i == curr.size()) return vediamo(u);
    for (int j = 0; j < curr.size(); j ++) {
        if (v[j]) continue;
        v[j] = 1;
        permutato.push_back(curr[j]);
        generate_permutation(u, i + 1);
        permutato.pop_back();
        v[j] = 0;
    }
}

void check(int u) {
    v.assign(curr.size(), 0);
    permutato.clear();
    // cout << "curr_size di " << u << " e " << curr.size() << '\n';
    permutato.push_back(u);
    generate_permutation(u, 0);
}

void dfs(int u) {
    // cout << "dfs " << u << '\n';
    curr.push_back(u);

    for (auto x : adj[u]) {
        if (x == P[u]) continue;
        dfs(x);
    }
}

vector<int> lentissimo(int N, int M, vector<int> P, vector<int> C) {
    ::P = P;
    ::C = C;
    for (int i = 1; i < N; i ++) {
        adj[P[i]].push_back(i);
        adj[i].push_back(P[i]);
    }

    fill(sol, sol + N, 0);
    fill(colori_usati, colori_usati + MAXM, 0);

    for (int i = 0; i < N; i ++) {
        // cout << "i : " << i << '\n';
        curr.clear();
        
        for (auto x : adj[i]) {
            if (x == P[i]) continue;
            dfs(x);
        }

        // cout << "fatto dfs: curr ";
        // for (auto x : curr) cout << x << " ";
        // cout << '\n';

        // cout << "curr per " << i << " : ";
        // for (auto x : curr) cout << x << " ";
        // cout << '\n';

        // cout << "ora check" << '\n';

        check(i);
    }

    vector<int> res(N);
    for (int i = 0; i < N; i ++) res[i] = sol[i];
    return res;
}

vector<int> path(int N, int M, vector<int> P, vector<int> C) {
    fill(sol, sol + N, 0);

    vector<int> res(N);

    int last_used = C[N - 1];
    int stronzo = 1e9;
    bool funzia = 1;
    for (int i = N - 1; i >= 0; i --) {

        res[i] = funzia;

        if (last_used != C[i]) {
            funzia = 0;
        }
    }

    return res;
}

vector<int> beechtree(int N, int M, vector<int> P, vector<int> C) {
    if (N <= 8) return lentissimo(N, M, P, C);
    return path(N, M, P, C);
}

Compilation message (stderr)

beechtree.cpp: In function 'void vediamo(int)':
beechtree.cpp:30:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |     for (int i = 1; i < permutato.size(); i ++) {
      |                     ~~^~~~~~~~~~~~~~~~~~
beechtree.cpp: In function 'void generate_permutation(int, int)':
beechtree.cpp:59:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |     if (i == curr.size()) return vediamo(u);
      |         ~~^~~~~~~~~~~~~~
beechtree.cpp:60:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |     for (int j = 0; j < curr.size(); j ++) {
      |                     ~~^~~~~~~~~~~~~
beechtree.cpp: In function 'std::vector<int> path(int, int, std::vector<int>, std::vector<int>)':
beechtree.cpp:132:9: warning: unused variable 'stronzo' [-Wunused-variable]
  132 |     int stronzo = 1e9;
      |         ^~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 9 / 9
• Subtask 2: 5 / 5
• Subtask 3: 0 / 9
• Subtask 4: 0 / 8
• Subtask 5: 0 / 14
• Subtask 6: 0 / 14
• Subtask 7: 0 / 12
• Subtask 8: 0 / 17
• Subtask 9: 0 / 12