oj.uz

Submission #747696

# Submission time Handle Problem Language Result Execution time Memory
747696 2023-05-24T13:36:49 Z GrindMachine Cat in a tree (BOI17_catinatree) C++17
100 / 100
 513 ms 44288 KB 
// Om Namah Shivaya

#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<typename 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;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#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 rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a, b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a, b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
https://github.com/thecodingwizard/competitive-programming/blob/master/BOI/BOI%2017-Cat.cpp

*/

const int MOD = 1e9 + 7;
const int N = 2e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

vector<int> adj[N];

struct lca_algo {
    // LCA template (for graphs with 1-based indexing)

    int LOG = 1;
    vector<int> depth;
    vector<vector<int>> up;

    lca_algo() {

    }

    lca_algo(int n) {
        lca_init(n);
    }

    void lca_init(int n) {
        while ((1 << LOG) < n) LOG++;
        up = vector<vector<int>>(n + 1, vector<int>(LOG));
        depth = vector<int>(n + 1);

        lca_dfs(0, -1);
    }

    void lca_dfs(int node, int par) {
        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;

            lca_dfs(child, node);
        }
    }

    int lift(int u, int k) {
        rep(j, LOG) {
            if (k & (1 << j)) {
                u = up[u][j];
            }
        }

        return u;
    }

    int query(int u, int v) {
        if (depth[u] < depth[v]) swap(u, v);
        int k = depth[u] - depth[v];
        u = lift(u, k);

        if (u == v) return u;

        rev(j, LOG - 1, 0) {
            if (up[u][j] != up[v][j]) {
                u = up[u][j];
                v = up[v][j];
            }
        }

        u = up[u][0];
        return u;
    }

    int get_dis(int u, int v) {
        int lca = query(u, v);
        return depth[u] + depth[v] - 2 * depth[lca];
    }
};

vector<int> subsiz(N);
vector<bool> rem(N);
vector<int> par(N);

int get_siz(int u, int p){
    subsiz[u] = 1;
    trav(v,adj[u]){
        if(v == p or rem[v]) conts;
        subsiz[u] += get_siz(v,u);
    }
    return subsiz[u];
}

int get_centroid(int u, int p, int nodes){
    trav(v, adj[u]){
        if(v == p or rem[v]) conts;
        if(subsiz[v] > nodes / 2){
            return get_centroid(v,u,nodes);
        }
    }

    return u;
}

void build(int u, int p){
    int nodes = get_siz(u,-1);
    int centroid = get_centroid(u,-1,nodes);

    par[centroid] = p;
    rem[centroid] = 1;

    trav(v, adj[centroid]){
        if(rem[v]) conts;
        build(v,centroid);
    }
}

void solve(int test_case)
{
    int n,d; cin >> n >> d;
    rep1(i,n){
        int p; cin >> p;
        adj[p].pb(i), adj[i].pb(p);
    }

    lca_algo LCA(n);
    build(0,-1);

    vector<pii> order;
    rep(i,n){
        order.pb({LCA.depth[i],i});
    }

    sort(rall(order));

    vector<int> best(n,inf1);
    int ans = 0;

    for(auto [dep, u] : order){
        // find closest active guy
        // similar to cf xenia and tree
        int mnd = inf1;
        int lca = u;

        while(lca != -1){
            int du = LCA.get_dis(u,lca);
            int d = du + best[lca];
            amin(mnd, d);
            lca = par[lca];
        }

        if(mnd >= d){
            // activate
            ans++;

            lca = u;
            while(lca != -1){
                int du = LCA.get_dis(u,lca);
                amin(best[lca], du);
                lca = par[lca];
            }
        }
    }

    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 6612 KB Output is correct
2 Correct 3 ms 6612 KB Output is correct
3 Correct 3 ms 6612 KB Output is correct
4 Correct 3 ms 6612 KB Output is correct
5 Correct 3 ms 6612 KB Output is correct
6 Correct 3 ms 6612 KB Output is correct
7 Correct 4 ms 6612 KB Output is correct
8 Correct 4 ms 6612 KB Output is correct
9 Correct 3 ms 6612 KB Output is correct
10 Correct 4 ms 6612 KB Output is correct
11 Correct 4 ms 6612 KB Output is correct
12 Correct 3 ms 6612 KB Output is correct
13 Correct 4 ms 6612 KB Output is correct
14 Correct 3 ms 6620 KB Output is correct
15 Correct 4 ms 6612 KB Output is correct
16 Correct 3 ms 6612 KB Output is correct
17 Correct 4 ms 6580 KB Output is correct
18 Correct 3 ms 6612 KB Output is correct
19 Correct 4 ms 6612 KB Output is correct
20 Correct 3 ms 6612 KB Output is correct

Subtask #2
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 6612 KB Output is correct
2 Correct 3 ms 6612 KB Output is correct
3 Correct 3 ms 6612 KB Output is correct
4 Correct 3 ms 6612 KB Output is correct
5 Correct 3 ms 6612 KB Output is correct
6 Correct 3 ms 6612 KB Output is correct
7 Correct 4 ms 6612 KB Output is correct
8 Correct 4 ms 6612 KB Output is correct
9 Correct 3 ms 6612 KB Output is correct
10 Correct 4 ms 6612 KB Output is correct
11 Correct 4 ms 6612 KB Output is correct
12 Correct 3 ms 6612 KB Output is correct
13 Correct 4 ms 6612 KB Output is correct
14 Correct 3 ms 6620 KB Output is correct
15 Correct 4 ms 6612 KB Output is correct
16 Correct 3 ms 6612 KB Output is correct
17 Correct 4 ms 6580 KB Output is correct
18 Correct 3 ms 6612 KB Output is correct
19 Correct 4 ms 6612 KB Output is correct
20 Correct 3 ms 6612 KB Output is correct
21 Correct 5 ms 6996 KB Output is correct
22 Correct 4 ms 6612 KB Output is correct
23 Correct 4 ms 6612 KB Output is correct
24 Correct 5 ms 6612 KB Output is correct
25 Correct 4 ms 6740 KB Output is correct
26 Correct 4 ms 6740 KB Output is correct
27 Correct 4 ms 6660 KB Output is correct
28 Correct 5 ms 6740 KB Output is correct
29 Correct 4 ms 6792 KB Output is correct
30 Correct 5 ms 6740 KB Output is correct
31 Correct 5 ms 6868 KB Output is correct
32 Correct 4 ms 6740 KB Output is correct
33 Correct 4 ms 6740 KB Output is correct
34 Correct 4 ms 6740 KB Output is correct
35 Correct 4 ms 6740 KB Output is correct
36 Correct 4 ms 6740 KB Output is correct
37 Correct 4 ms 6740 KB Output is correct
38 Correct 4 ms 6796 KB Output is correct
39 Correct 5 ms 6868 KB Output is correct
40 Correct 5 ms 6868 KB Output is correct

Subtask #3
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 6612 KB Output is correct
2 Correct 3 ms 6612 KB Output is correct
3 Correct 3 ms 6612 KB Output is correct
4 Correct 3 ms 6612 KB Output is correct
5 Correct 3 ms 6612 KB Output is correct
6 Correct 3 ms 6612 KB Output is correct
7 Correct 4 ms 6612 KB Output is correct
8 Correct 4 ms 6612 KB Output is correct
9 Correct 3 ms 6612 KB Output is correct
10 Correct 4 ms 6612 KB Output is correct
11 Correct 4 ms 6612 KB Output is correct
12 Correct 3 ms 6612 KB Output is correct
13 Correct 4 ms 6612 KB Output is correct
14 Correct 3 ms 6620 KB Output is correct
15 Correct 4 ms 6612 KB Output is correct
16 Correct 3 ms 6612 KB Output is correct
17 Correct 4 ms 6580 KB Output is correct
18 Correct 3 ms 6612 KB Output is correct
19 Correct 4 ms 6612 KB Output is correct
20 Correct 3 ms 6612 KB Output is correct
21 Correct 5 ms 6996 KB Output is correct
22 Correct 4 ms 6612 KB Output is correct
23 Correct 4 ms 6612 KB Output is correct
24 Correct 5 ms 6612 KB Output is correct
25 Correct 4 ms 6740 KB Output is correct
26 Correct 4 ms 6740 KB Output is correct
27 Correct 4 ms 6660 KB Output is correct
28 Correct 5 ms 6740 KB Output is correct
29 Correct 4 ms 6792 KB Output is correct
30 Correct 5 ms 6740 KB Output is correct
31 Correct 5 ms 6868 KB Output is correct
32 Correct 4 ms 6740 KB Output is correct
33 Correct 4 ms 6740 KB Output is correct
34 Correct 4 ms 6740 KB Output is correct
35 Correct 4 ms 6740 KB Output is correct
36 Correct 4 ms 6740 KB Output is correct
37 Correct 4 ms 6740 KB Output is correct
38 Correct 4 ms 6796 KB Output is correct
39 Correct 5 ms 6868 KB Output is correct
40 Correct 5 ms 6868 KB Output is correct
41 Correct 140 ms 35048 KB Output is correct
42 Correct 247 ms 21500 KB Output is correct
43 Correct 179 ms 21528 KB Output is correct
44 Correct 163 ms 21568 KB Output is correct
45 Correct 181 ms 21572 KB Output is correct
46 Correct 513 ms 36532 KB Output is correct
47 Correct 450 ms 36472 KB Output is correct
48 Correct 469 ms 36512 KB Output is correct
49 Correct 431 ms 36528 KB Output is correct
50 Correct 108 ms 21964 KB Output is correct
51 Correct 111 ms 21960 KB Output is correct
52 Correct 117 ms 21988 KB Output is correct
53 Correct 270 ms 37356 KB Output is correct
54 Correct 253 ms 37404 KB Output is correct
55 Correct 272 ms 37376 KB Output is correct
56 Correct 5 ms 6996 KB Output is correct
57 Correct 31 ms 11436 KB Output is correct
58 Correct 177 ms 28488 KB Output is correct
59 Correct 505 ms 44288 KB Output is correct
60 Correct 152 ms 35780 KB Output is correct
61 Correct 264 ms 34884 KB Output is correct