Submission #707745

#	Time	Username	Problem	Language	Result	Execution time	Memory
707745		marvinthang	Towns (IOI15_towns)	C++17	100 / 100	21 ms	1088 KiB

towns

/*************************************
*    author: marvinthang             *
*    created: 08.03.2023 17:37:48    *
*************************************/

#include <bits/stdc++.h>
#include "towns.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 T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> scan_op(pair <U, V>)  { return in >> u.fi >> u.se; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
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 <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 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; }

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count()); 
long long rand(long long l, long long h) { return uniform_int_distribution <long long> (l, h) (rng); } 

// end of template

int hubDistance(int N, int sub) {
	vector <int> dist0(N), distu(N);
	FOR(i, 1, N) dist0[i] = getDistance(0, i);
	int u = max_element(ALL(dist0)) - dist0.begin();
	REP(i, N) if (i != u) distu[i] = getDistance(u, i);
	int diameter = *max_element(ALL(distu));
	int res = diameter;
	map <int, vector <int>> List;
	REP(i, N) {
		int dd = (distu[0] + distu[i] - dist0[i]) / 2;
		minimize(res, max(dd, diameter - dd));
		List[dd].push_back(i);
	}
	int cnt_left = 0;
	for (auto [dd, l]: List) {
		if (max(dd, diameter - dd) == res) {
			int cnt_right = N - cnt_left - (int) l.size();
			if (cnt_left <= N / 2 && cnt_right <= N / 2) {
				vector <vector <int>> alive, dead;
				vector <int> candidate;
				for (int u: l) alive.push_back(vector<int>{u});
				auto checkComp = [&] (int x, int y) {
					return distu[x] + distu[y] - getDistance(x, y) != 2 * dd;
				};
				while (!alive.empty()) {
					vector <vector <int>> nxt;
					for (int i = 0; i < (int) alive.size(); i += 2) {
						if (i + 1 == (int) alive.size()) {
							if (!candidate.empty()) dead.push_back(candidate);
							candidate = alive[i];
						} else {
							if (checkComp(alive[i][0], alive[i + 1][0])) {
								nxt.push_back(alive[i]);
								nxt.back().insert(nxt.back().end(), ALL(alive[i + 1]));
							} else {
								dead.push_back(alive[i]);
								dead.push_back(alive[i + 1]);
							}
						}
					}
					alive = move(nxt);
				}
				if (candidate.empty()) return res;
				int cnt = candidate.size();
				for (auto v: dead) if (checkComp(candidate[0], v[0])) cnt += v.size();
				if (cnt <= N / 2) return res;
			}
		}
		cnt_left += l.size();
	}
	return -res;
}

#ifdef LOCAL
#include "graderlib.c"

int main() {
    FILE *f;
    f = freopen("towns.in","r",stdin);
    assert(f != NULL);
    f = freopen("towns.out","w",stdout);
    assert(f != NULL);
    int ncase, R, N;
    int subtask;
    int ret;
    ret = scanf("%d%d",&subtask,&ncase);
    assert(ret == 2);
    for (int i = 0; i < ncase; i++) {
        ret = scanf("%d",&N);
	assert(ret == 1);
        _ini_query(N,subtask);
        R=hubDistance(N,subtask);
        printf("%d\n",R);
    }
    return 0;
}
#endif

Compilation message (stderr)

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:54:34: warning: conversion from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >::difference_type' {aka 'long int'} to 'int' may change value [-Wconversion]
   54 |  int u = max_element(ALL(dist0)) - dist0.begin();
      |          ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
towns.cpp:71:14: warning: declaration of 'u' shadows a previous local [-Wshadow]
   71 |     for (int u: l) alive.push_back(vector<int>{u});
      |              ^
towns.cpp:54:6: note: shadowed declaration is here
   54 |  int u = max_element(ALL(dist0)) - dist0.begin();
      |      ^
towns.cpp:94:29: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   94 |     int cnt = candidate.size();
      |               ~~~~~~~~~~~~~~^~
towns.cpp:95:73: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   95 |     for (auto v: dead) if (checkComp(candidate[0], v[0])) cnt += v.size();
      |                                                                         ^
towns.cpp:99:22: warning: conversion from 'std::vector<int>::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
   99 |   cnt_left += l.size();
      |                      ^
towns.cpp:51:28: warning: unused parameter 'sub' [-Wunused-parameter]
   51 | int hubDistance(int N, int sub) {
      |                        ~~~~^~~

• Subtask 1: 13 / 13
• Subtask 2: 12 / 12
• Subtask 3: 13 / 13
• Subtask 4: 10 / 10
• Subtask 5: 13 / 13
• Subtask 6: 39 / 39