Submission #1123397

#	Time	Username	Problem	Language	Result	Execution time	Memory
1123397		Whisper	Mergers (JOI19_mergers)	C++20	0 / 100	88 ms	47288 KiB

mergers

#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, a) for (int i = 0; i < (a); ++i)
#define REPD(i, a) for (int i = (a) - 1; i >= 0; --i)

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


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

/*
    Phu Trong from Nguyen Tat Thanh High School for gifted student
*/

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;
    }
#define MAX                         500005

int numNode, numState, label[MAX];
vector<int> G[MAX];

int cntState[MAX];

map<int, int> cnt[MAX];
int ans = 0;
int lab[MAX];
int fp(int u){
    return (lab[u] < 0 ? u : lab[u] = fp(lab[u]));
}
bool joint (int u, int v){
    u = fp(u), v = fp(v);
    if(u == v) return false;

    if(lab[u] > lab[v]) swap(u, v);
    lab[u] += lab[v];
    lab[v] = u;
    return true;
}


void dfs(int u, int p = -1){
    cnt[u][label[u]] = 1;
    if(cnt[u][label[u]] == cntState[label[u]]){
        cnt[u].erase(cnt[u].find(label[u]));
    }

    for (int&v : G[u]) if(v ^ p){
        dfs(v, u);
        if((int)cnt[u].size() < (int)cnt[v].size()){
            swap(cnt[u], cnt[v]);
        }
        for (auto&x : cnt[v]){
            cnt[u][x.first] += x.second;
            if(cntState[x.first] == cnt[u][x.first]){
                cnt[u].erase(cnt[u].find(x.first));
            }
        }
    }

    if(p != -1){
        if(!cnt[u].empty()){
            joint(u, p);
        }
    }
}

int deg[MAX];
void process(void){
    cin >> numNode >> numState;
    for (int i = 1; i < numNode; ++i){
        int u, v; cin >> u >> v;
        G[u].emplace_back(v);
        G[v].emplace_back(u);
    }
    for (int i = 1; i <= numNode; ++i){
        cin >> label[i];
        cntState[label[i]]++;
    }
    for (int i = 1; i <= numNode; ++i) lab[i] = -1;
    dfs(1);

    for (int u = 1; u <= numNode; ++u){
        for (int&v : G[u]) {
            if(fp(u) != fp(v)){
                ++deg[u];
            }
        }
    }
    for (int u = 1; u <= numNode; ++u) ans += (deg[u] == 1);
    cout << (ans + 1) / 2;
}
signed main(){
    #define name "Whisper"
    cin.tie(nullptr) -> sync_with_stdio(false);
    // freopen(name".inp", "r", stdin);
    // freopen(name".out", "w", stdout);
    process();
    return (0 ^ 0);
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 24
• Subtask 3: 0 / 14
• Subtask 4: 0 / 22
• Subtask 5: 0 / 30