Submission #428696

#	Time	Username	Problem	Language	Result	Execution time	Memory
428696		talant117408	Capital City (JOI20_capital_city)	C++17	100 / 100	1002 ms	43584 KiB

capital_city

/*
    Code written by Talant I.D.
*/
 
#include <bits/stdc++.h>
//~ #include <ext/pb_ds/assoc_container.hpp>
 
//~ using namespace __gnu_pbds;
using namespace std;
 
typedef long long ll;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;
//~ typedef tree <int, null_type, less <int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
 
#define precision(n) fixed << setprecision(n)
#define pb push_back
#define ub upper_bound
#define lb lower_bound
#define mp make_pair
#define eps (double)1e-9
#define PI 2*acos(0.0)
#define endl "\n"
#define sz(v) int((v).size())
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define do_not_disturb ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define OK cout << "OK" << endl;
 
const int mod = 1e9+7;
 
ll mode(ll a) {
    while (a < 0) {
        a += mod;
    }
    return a % mod;
}
 
ll subt(ll a, ll b) {
    return mode(mode(a)-mode(b));
}
 
ll add(ll a, ll b) {
    return mode(mode(a)+mode(b));
}
 
ll mult(ll a, ll b) {
    return mode(mode(a)*mode(b));
}
 
ll binpow(ll a, ll b) {
    ll res = 1;
    while (b) {
        if (b&1) res = mult(res, a);
        a = mult(a, a);
        b >>= 1;
    }
    return res;
}

const int N = 2e5+7;
vector <int> graph[N], byColor[N];
int par[N], color[N], ind[N], timer, saizu[N], vis[N];
int ans, root_size, n;

void find_size(int v, int p) {
    saizu[v] = 1;
    for (auto to : graph[v]) {
        if (vis[to] || to == p) continue;
        find_size(to, v);
        saizu[v] += saizu[to];
    }
}

int find_centroid(int v, int p) {
    for (auto to : graph[v]) {
        if (vis[to] || to == p) continue;
        if (saizu[to]*2 > root_size) {
            return find_centroid(to, v);
        }
    }
    return v;
}

void create_tree(int v, int p) {
    ind[v] = timer;
    par[v] = p;
    for (auto to : graph[v]) {
        if (vis[to] || to == p) continue;
        create_tree(to, v);
    }
}

void init_centroid(int u) {
    find_size(u, u);
    root_size = saizu[u];
    int centroid = find_centroid(u, u);
    vis[centroid] = 1;
    create_tree(centroid, centroid);
    
    queue <int> K;
    set <int> colors;
    bool outside = 1;
    colors.insert(color[centroid]);
    for (auto to : byColor[color[centroid]]) {
        K.push(to);
        if (ind[to] != timer) {
            outside = 0;
            break;
        }
    }
    while (sz(K)) {
        if (!outside) {
            break;
        }
        int v = K.front(); K.pop();
        if (ind[v] != timer) {
            outside = 0;
            break;
        }
        if (color[par[v]] != color[v]) {
            auto it = colors.lb(color[par[v]]);
            if (it == colors.end() || *it != color[par[v]]) {
                colors.insert(color[par[v]]);
                for (auto to : byColor[color[par[v]]]) {
                    K.push(to);
                    if (ind[to] != timer) {
                        outside = 0;
                        break;
                    }
                }
            }
        }
    }
    if (outside) {
        ans = min(ans, sz(colors)-1);
    }
    for (auto to : graph[centroid]) {
        if (!vis[to]) {
            timer++;
            init_centroid(to);
        }
    }
}

int main() {
    do_not_disturb
    
    int k;
    cin >> n >> k;
    ans = k+1;
    for (int i = 0; i < n-1; i++) {
        int x, y;
        cin >> x >> y;
        graph[x].pb(y);
        graph[y].pb(x);
    }
    for (int i = 1; i <= n; i++) {
        cin >> color[i];
        byColor[color[i]].pb(i);
    }
    
    init_centroid(1);
    cout << ans;
    
    return 0;
}

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