Submission #941340

#	Time	Username	Problem	Language	Result	Execution time	Memory
941340		a_l_i_r_e_z_a	Capital City (JOI20_capital_city)	C++17	11 / 100	6 ms	12892 KiB

capital_city

// In the name of God
// Hope is last to die
 
#include <bits/stdc++.h>
using namespace std;
 
// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2")
 
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
 
#define pb push_back
// #define int long long
#define S second
#define F first
#define mp make_pair
#define smax(x, y) (x) = max((x), (y))
#define smin(x, y) (x) = min((x), (y))
#define all(x) (x).begin(), (x).end()
 
const int maxn = 1e5 + 5;
const int inf = 1e9 + 7;
int n, k, a[maxn], sz[maxn], par[maxn], id[maxn];
vector<int> adj[maxn], vec[maxn];
bool mark[maxn], vis[maxn];
queue<int> q;

int get_sz(int v, int p = -1){
    sz[v] = 1;
    for(auto u: adj[v]){
        if(u != p && !mark[u]) sz[v] += get_sz(u, v);
    }
    return sz[v];
}

int find(int v, int p, int s){
    for(auto u: adj[v]){
        if(u != p && !mark[u] && sz[u] * 2 > s) return find(u, v, s);
    }
    return v;
}

void dfs(int v, int p, int r){
    vis[a[v]] = 0;
    par[v] = p;
    id[v] = r;
    for(auto u: adj[v]){
        if(u != p && !mark[u]) dfs(u, v, r);
    }
}

int centroid_decompose(int v){
    v = find(v, 0, get_sz(v));
    dfs(v, v, v);
    q.push(a[v]);
    int ans = 0;
    while(q.size()){
        int c = q.front();
        q.pop();
        if(vis[c]) continue;
        vis[c] = 1;
        for(auto u: vec[c]){
            if(id[u] != v){
                ans = k;
                break;
            }
            q.push(a[par[u]]);
        }
        ans++;
    }
    mark[v] = 1;
    for(auto u: adj[v]) if(!mark[u]) smin(ans, centroid_decompose(u));
    return ans;
}

int32_t main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    cin >> n >> k;
    for(int i = 0; i < n - 1; i++){
        int u, v; cin >> u >> v;
        adj[u].pb(v);
        adj[v].pb(u);
    }
    for(int i = 1; i <= n; i++){
        cin >> a[i];
        vec[a[i]].pb(i);
    }
    cout << centroid_decompose(1) - 1 << '\n';

    return 0;
}

• Subtask 1: 1 / 1
• Subtask 2: 10 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 59