Submission #960752

#	Time	Username	Problem	Language	Result	Execution time	Memory
960752		GrindMachine	Capital City (JOI20_capital_city)	C++17	0 / 100	319 ms	39436 KiB

capital_city

#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) (int)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

/*

read the solution a long time ago, remember the solution idea

*/

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

void dfs1(int u, int p){
    nodes.pb(u);
    subsiz[u] = 1;
    par[u] = p;
    trav(v,adj[u]){
        if(v == p or rem[v]) conts;
        dfs1(v,u);
        subsiz[u] += subsiz[v];
    }
}

int dfs2(int u, int p, int nodes){
    trav(v,adj[u]){
        if(v == p or rem[v]) conts;
        if(subsiz[v] > nodes/2){
            return dfs2(v,u,nodes);
        }
    }
    return u;
}

vector<int> here[N];
vector<bool> vis(N), done(N);
vector<int> tot_cnt(N);

int go(int u){
    nodes.clear();
    dfs1(u,-1);
    int c = dfs2(u,-1,sz(nodes));

    trav(v,nodes){
        here[a[v]].pb(v);
    }

    queue<int> q;
    q.push(a[c]);
    vis[a[c]] = 1;
    int cols = 0;
    bool ok = true;

    while(!q.empty()){
        int col = q.front();
        q.pop();

        cols++;
        if(sz(here[col]) != tot_cnt[col]){
            ok = false;
        }

        trav(u,here[col]){
            int v = u;
            while(v != -1 and !done[v]){
                if(!vis[a[v]]){
                    q.push(a[v]);
                    vis[a[v]] = 1;
                }

                done[v] = 1;
                v = par[v];
            }
        }
    }

    int ans = inf1;
    if(ok){
        ans = cols-1;
    }

    trav(v,nodes){
        here[a[v]].clear();
        vis[a[v]] = done[v] = 0;
    }

    rem[c] = 1;
    
    trav(v,adj[c]){
        if(rem[v]) conts;
        amin(ans,go(v));
    }

    return ans;
}

void solve(int test_case)
{
    int n,k; cin >> n >> k;
    rep1(i,n-1){
        int u,v; cin >> u >> v;
        adj[u].pb(v), adj[v].pb(u);
    }
    rep1(i,n) cin >> a[i];
    rep1(i,n) tot_cnt[a[i]]++;

    int ans = go(1);
    cout << ans << endl;
}

int main()
{
    fastio;

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

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

    return 0;
}

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