Submission #883275

#	Time	Username	Problem	Language	Result	Execution time	Memory
883275		marvinthang	Capital City (JOI20_capital_city)	C++17	100 / 100	456 ms	42128 KiB

capital_city

/*************************************
*    author: marvinthang             *
*    created: 05.12.2023 09:58:14    *
*************************************/

#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i-- > 0; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }

// end of template

void process(void) {
	int n, k; cin >> n >> k;
	vector <vector <int>> adj(n);
	REP(i, n - 1) {
		int u, v; cin >> u >> v; --u; --v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	vector <int> c(n);
	vector <vector <int>> list_idx(k);
	REP(i, n) {
		cin >> c[i];
		list_idx[--c[i]].push_back(i);
	}
	vector <bool> used(n), exist(k);
	vector <int> sz(n), par(n), cnt(k);
	function<void(int, int)> dfs_sz = [&] (int u, int par) {
		sz[u] = 1;
		exist[c[u]] = false;
		cnt[c[u]] = 0;
		for (int v: adj[u]) if (!used[v] && v != par) {
			dfs_sz(v, u);
			sz[u] += sz[v];
		}
	};
	function<int(int, int, int)> find = [&] (int u, int par, int n) {
		for (int v: adj[u]) if (!used[v] && v != par && sz[v] >= n / 2) return find(v, u, n);
		return u;
	};
	int res = k - 1;
	function<void(int)> solve = [&] (int u) {
		dfs_sz(u, -1);
		u = find(u, -1, sz[u]);
		par[u] = -1;
		function<void(int)> dfs = [&] (int u) {
			++cnt[c[u]];
			for (int v: adj[u]) if (!used[v] && v != par[u]) {
				par[v] = u;
				dfs(v);
			}
		};
		dfs(u);
		queue <int> q;
		q.push(c[u]);
		int cc = 0;
		exist[c[u]] = true;
		while (!q.empty()) {
			int f = q.front(); q.pop();
			if (cnt[f] != (int) list_idx[f].size()) {
				cc = k;
				break;
			}
			++cc;
			for (int u: list_idx[f]) {
				u = par[u];
				if (u >= 0 && !exist[c[u]]) {
					exist[c[u]] = true;
					q.push(c[u]);
				}
			}
		}
		res = min(res, cc - 1);
		used[u] = true;
		for (int v: adj[u]) if (!used[v]) solve(v);
	};
	solve(0);
	cout << res << '\n';
}

int main(void) {
	ios_base::sync_with_stdio(false); cin.tie(nullptr); // cout.tie(nullptr);
	file("JOI20_capital_city");
	// int t; cin >> t; while (t--)
	process();
	// cerr << "Time elapsed: " << TIME << " s.\n";
	return (0^0);
}

Compilation message (stderr)

capital_city.cpp: In function 'int main()':
capital_city.cpp:30:61: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
capital_city.cpp:116:2: note: in expansion of macro 'file'
  116 |  file("JOI20_capital_city");
      |  ^~~~
capital_city.cpp:30:94: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
capital_city.cpp:116:2: note: in expansion of macro 'file'
  116 |  file("JOI20_capital_city");
      |  ^~~~

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