Submission #376948

#	Time	Username	Problem	Language	Result	Execution time	Memory
376948		wiwiho	Mergers (JOI19_mergers)	C++14	100 / 100	1396 ms	174464 KiB

mergers

#include <bits/stdc++.h>
#include <bits/extc++.h>

#define StarBurstStream ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define iter(a) a.begin(), a.end()
#define riter(a) a.rbegin(), a.rend()
#define lsort(a) sort(iter(a))
#define gsort(a) sort(riter(a))
#define pb(a) push_back(a)
#define eb(a) emplace_back(a)
#define pf(a) push_front(a)
#define ef(a) emplace_front(a)
#define pob pop_back()
#define pof pop_front()
#define mp(a, b) make_pair(a, b)
#define F first
#define S second
#define mt make_tuple
#define gt(t, i) get<i>(t)
#define iceil(a, b) (((a) + (b) - 1) / (b))
#define tomax(a, b) ((a) = max((a), (b)))
#define tomin(a, b) ((a) = min((a), (b)))
#define topos(a) ((a) = (((a) % MOD + MOD) % MOD))
#define uni(a) a.resize(unique(iter(a)) - a.begin())
#define printv(a, b) {bool pvaspace=false; \
for(auto pva : a){ \
    if(pvaspace) b << " "; pvaspace=true;\
    b << pva;\
}\
b << "\n";}

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<ld, ld>;
using tiii = tuple<int, int, int>;

const ll MOD = 1000000007;
const ll MAX = 2147483647;

template<typename A, typename B>
ostream& operator<<(ostream& o, pair<A, B> p){
    return o << '(' << p.F << ',' << p.S << ')';
}

vector<vector<int>> g;
vector<int> s, cnt;
vector<map<int, int>> st;
stack<int> stk;
vector<int> id;
int ts = 0;
void dfs(int now, int p){
    stk.push(now);
    st[now][s[now]]++;
    if(st[now][s[now]] == cnt[s[now]]) st[now].erase(s[now]);
    for(int i : g[now]){
        if(i == p) continue;
        dfs(i, now);
        if(st[now].size() < st[i].size()) st[now].swap(st[i]);
        for(pii j : st[i]){
            st[now][j.F] += j.S;
            if(st[now][j.F] == cnt[j.F]) st[now].erase(j.F);
        }
    }
    if(st[now].empty()){
        while(true){
            int v = stk.top();
            id[v] = ts;
            stk.pop();
            if(v == now) break;
        }
        ts++;
    }
}

int main(){
    StarBurstStream

    int n, k;
    cin >> n >> k;

    g.resize(n + 1);
    s.resize(n + 1);
    cnt.resize(k + 1);
    st.resize(n + 1);
    id.resize(n + 1);

    for(int i = 0; i < n - 1; i++){
        int u, v;
        cin >> u >> v;
        g[u].eb(v);
        g[v].eb(u);
    }
    for(int i = 1; i <= n; i++){
        cin >> s[i];
        cnt[s[i]]++;
    }

    dfs(1, 1);
//    printv(id, cerr);
    vector<set<int>> deg(ts);
    for(int i = 1; i <= n; i++){
        for(int j : g[i]){
            if(id[i] != id[j]) deg[id[i]].insert(id[j]);
        }
    }

    int o = 0;
    for(int i = 0; i < ts; i++){
//        cerr << i << "  ";
//        printv(deg[i], cerr);
        if(deg[i].size() == 1) o++;
    }
    if(o == 1) cout << "0\n";
    else cout << (o + 1) / 2 << "\n";

    return 0;
}

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