Submission #736169

#	Time	Username	Problem	Language	Result	Execution time	Memory
736169		marvinthang	Papričice (COCI20_papricice)	C++17	110 / 110	188 ms	21576 KiB

papricice

/*************************************
*    author: marvinthang             *
*    created: 05.05.2023 15:57:36    *
*************************************/

#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--; )
#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 << '}'; }
template <class A, class B> bool minimize(A &a, B b)  { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b)  { if (a < b) { a = b; return true; } return false; }

// end of template

const int MAX = 2e5 + 5;
const int INF = 1e9;

int N, treeSize[MAX], res = INF;
vector <int> adj[MAX];

void init(void) {
	cin >> N;
	FOR(i, 1, N) {
		int u, v; cin >> u >> v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
}

void dfs(int u, int par) {
	treeSize[u] = 1;
	for (int v: adj[u]) if (v != par) {
		dfs(v, u);
		treeSize[u] += treeSize[v];
	}
}

set <int> in, out;

int get_val(int a, int b, int c) {
	return max({a, b, c}) - min({a, b, c});
}

void dfs2(int u, int par) {
	auto it = in.upper_bound((N + treeSize[u]) / 2);
	if (it != in.end()) minimize(res, get_val(treeSize[u], N - *it, *it - treeSize[u]));
	if (it != in.begin()) {
		--it;
		minimize(res, get_val(treeSize[u], N - *it, *it - treeSize[u]));
	}
	it = out.upper_bound((N - treeSize[u]) / 2);
	if (it != out.end()) minimize(res, get_val(treeSize[u], N - *it - treeSize[u], *it));
	if (it != out.begin()) {
		--it;
		minimize(res, get_val(treeSize[u], N - *it - treeSize[u], *it));
	}

	in.insert(treeSize[u]);
	for (int v: adj[u]) if (v != par) dfs2(v, u);
	in.erase(treeSize[u]);
	out.insert(treeSize[u]);
}

void process(void) {
	dfs(1, 0);
	dfs2(1, 0);
	cout << res << '\n';
}

int main(void) {
	ios_base::sync_with_stdio(false); cin.tie(nullptr); // cout.tie(nullptr);
	file("coci2021_r1_papricice");
	init();
	process();
	// cerr << "Time elapsed: " << TIME << " s.\n";
	return (0^0);
}

Compilation message (stderr)

papricice.cpp: In function 'int main()':
papricice.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); }
      |                                                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
papricice.cpp:104:2: note: in expansion of macro 'file'
  104 |  file("coci2021_r1_papricice");
      |  ^~~~
papricice.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); }
      |                                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
papricice.cpp:104:2: note: in expansion of macro 'file'
  104 |  file("coci2021_r1_papricice");
      |  ^~~~

• Subtask 1: 15 / 15
• Subtask 2: 35 / 35
• Subtask 3: 60 / 60