제출 #306956

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
306956		HynDuf	Mergers (JOI19_mergers)	C++11	100 / 100	840 ms	87724 KiB

mergers

#include <bits/stdc++.h>

#define task "M"
#define all(v) (v).begin(), (v).end()
#define rep(i, l, r) for (int i = (l); i <= (r); ++i)
#define Rep(i, r, l) for (int i = (r); i >= (l); --i)
#define DB(X) { cerr << #X << " = " << (X) << '\n'; }
#define DB1(A, _) { cerr << #A << "[" << _ << "] = " << (A[_]) << '\n'; }
#define DB2(A, _, __) { cerr << #A << "[" << _ << "][" << __ << "] = " << (A[_][__]) << '\n'; }
#define DB3(A, _, __, ___) { cerr << #A << "[" << _ << "][" << __ << "][" << ___ << "] = " << (A[_][__][___]) << '\n'; }
#define PR(A, l, r) { cerr << '\n'; rep(_, l, r) DB1(A, _); cerr << '\n';}
#define SZ(x) ((int)(x).size())
#define pb push_back
#define eb emplace_back
#define pf push_front
#define F first
#define S second
#define by(x) [](const auto& a, const auto& b) { return a.x < b.x; } // sort(arr, arr + N, by(a));
#define next ___next
#define prev ___prev
#define y1 ___y1
#define left ___left
#define right ___right
#define y0 ___y0
#define div ___div
#define j0 ___j0
#define jn ___jn

using ll = long long;
using ld = long double;
using ull = unsigned long long;
using namespace std;
typedef pair<int, int> ii;
typedef pair<ii, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<ll> vl;
const int N = 5e5 + 2;
int n, numCol, deg[N], rt[N], dep[N], par[N];
vi col[N], g[N];
void dfs(int u)
{
    dep[u] = dep[par[u]] + 1;
    for (int v : g[u]) if (v != par[u])
    {
        par[v] = u;
        dfs(v);
    }
}
int frt(int i) {return rt[i] == i ? i : rt[i] = frt(rt[i]);}
bool in[N];
int main()
{
#ifdef HynDuf
    freopen(task".in", "r", stdin);
    //freopen(task".out", "w", stdout);
#else
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
#endif
    cin >> n >> numCol;
    rep(I, 2, n)
    {
        int u, v;
        cin >> u >> v;
        g[u].eb(v);
        g[v].eb(u);
    }
    dfs(1);
    rep(i, 1, n)
    {
        int c;
        cin >> c;
        col[c].eb(i);
        rt[i] = i;
    }
    rep(c, 1, numCol)
    {
        rep(i, 1, SZ(col[c]) - 1)
        {
            int u = frt(col[c][i - 1]), v = frt(col[c][i]);
            while (u != v)
            {
                if (dep[u] < dep[v]) swap(u, v);
                rt[u] = frt(par[u]);
                u = rt[u];
            }
        }
    }
    vi change;
    rep(i, 1, n)
    {
        for (int v : g[i]) if (frt(v) != frt(i) && !in[frt(v)]) change.eb(frt(v)), in[frt(v)] = 1, deg[frt(v)]++;
        for (int v : change) in[v] = 0;
        change.clear();
    }
    int cnt = 0;
    rep(i, 1, n) cnt += (deg[i] == 1);
    cout << (cnt + 1) / 2;
    return 0;
}

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