Submission #938994

#	Time	Username	Problem	Language	Result	Execution time	Memory
938994		Whisper	Capital City (JOI20_capital_city)	C++17	100 / 100	569 ms	44820 KiB

capital_city

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#define int long long
#define FOR(i, a, b) for ( int i = a ; i <= b ; i++ )
#define FORD(i, a, b) for (int i = b; i >= a; i --)
#define REP(i, n) for (int i = 0; i < n; ++i)
#define REPD(i, n) for (int i = n - 1; i >= 0; --i)
#define Lg(x) 31 - __builtin_clz(x)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)

constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int MAX = 2e5 + 5;
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

void setupIO(){
    #define name "Whisper"
    //Phu Trong from Nguyen Tat Thanh High School for gifted student
    srand(time(NULL));
    cin.tie(nullptr)->sync_with_stdio(false); cout.tie(nullptr);
    //freopen(name".inp", "r", stdin);
    //freopen(name".out", "w", stdout);
    cout << fixed << setprecision(10);
}

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }
int numNode, numCity;
vector<int> G[MAX];
int C[MAX];
int sz[MAX], del[MAX];
void reSubsize(int u, int p = -1){
    sz[u] = 1;
    for (int &v : G[u])if (v ^ p){
        if (del[v]) continue;
        reSubsize(v, u);
        sz[u] += sz[v];
    }
}
int getCentroid(int u, int p, int siz){
    for (int &v : G[u]) if(v ^ p){
        if (2 * sz[v] > siz && !del[v]) return getCentroid(v, u, siz);
    }
    return u;
}
int cnt[MAX], vis[MAX], par[MAX];
vector<int> color[MAX];
void dfs(int u, int p, bool ok){
    if (ok){
        color[C[u]].push_back(u); par[u] = p;
    }
    else{
        color[C[u]].clear(); vis[C[u]] = 0;
    }
    for (int&v : G[u]) if(v ^ p){
        if (!del[v]) dfs(v, u, ok);
    }
}
int ans = INF;
void decompose(int root){
    reSubsize(root);
    int siz = sz[root];
    root = getCentroid(root, -1, siz);
    dfs(root, root, 1);
    del[root] = 1;
    int ret = 0;
    bool full = 1;
    queue<int> q;
    q.emplace(C[root]); vis[C[root]] = 1;
    while (!q.empty()){
        int current_color = q.front(); q.pop();
        if ((int)color[current_color].size() != cnt[current_color]){full = 0; continue;}
        for (int &node : color[current_color]){
            int p = par[node];
            if (!vis[C[p]]){
                vis[C[p]] = 1;
                q.emplace(C[p]); ++ ret;
            }
        }
    }
    dfs(root, root, 0);
    if (full) minimize(ans, ret);
    for (int &v : G[root]){
        if (!del[v]) decompose(v);
    }
}
void Whisper(){
    cin >> numNode >> numCity;
    for (int i = 1; i < numNode; ++i){
        int u, v; cin >> u >> v;
        G[u].push_back(v);
        G[v].push_back(u);
    }
    for (int i = 1; i <= numNode; ++i){
        cin >> C[i];
        cnt[C[i]]++;
    }

    decompose(1);
    cout << ans;
}


signed main(){
    setupIO();
    int Test = 1;
//    cin >> Test;
    for ( int i = 1 ; i <= Test ; i++ ){
        Whisper();
        if (i < Test) cout << '\n';
    }
}

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