Submission #533905

#	Time	Username	Problem	Language	Result	Execution time	Memory
533905		Bungmint	Palembang Bridges (APIO15_bridge)	C++17	100 / 100	358 ms	13608 KiB

bridge

//Copyright © 2022 Youngmin Park. All rights reserved.
//#pragma GCC optimize("O3")
//#pragma GCC target("avx2")
#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using vi = vector<int>;
using pii = pair<int, int>;
using vpi = vector<pii>;
using pll = pair<ll, ll>;
using vl = vector<ll>;
using vpl = vector<pll>;
using ld = long double;
template <typename T, size_t SZ>
using ar = array<T, SZ>;

#define all(v) (v).begin(), (v).end()
#define pb push_back
#define sz(x) (int)(x).size()
#define fi first
#define se second
#define lb lower_bound
#define ub upper_bound
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i, a) ROF(i, 0, a)
#define REP(a) F0R(_, a)

const int INF = 1e9;
const ll LINF = 1e18;
const int MOD = 1e9 + 7; //998244353;
const ld PI = acos((ld)-1.0);
const int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T>
using pqg = priority_queue<T, vector<T>, greater<T>>;
template <typename T>
bool ckmin(T &a, const T &b) { return b < a ? a = b, 1 : 0; }
template <typename T>
bool ckmax(T &a, const T &b) { return b > a ? a = b, 1 : 0; }

template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p)
{
    return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v)
{
    os << '{';
    string sep;
    for (const T &x : v)
        os << sep << x, sep = ", ";
    return os << '}';
}
void dbg_out()
{
    cerr << endl;
}
template <typename Head, typename... Tail>
void dbg_out(Head H, Tail... T)
{
    cerr << ' ' << H;
    dbg_out(T...);
}
#ifdef LOCAL
#define dbg(...) cerr << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
#else
#define dbg(...) 42
#endif

inline namespace RecursiveLambda{
	template <typename Fun>
	struct y_combinator_result{
		Fun fun_;
		template <typename T> 
		explicit y_combinator_result(T &&fun): fun_(forward<T>(fun)){}
		template <typename...Args>
		decltype(auto) operator()(Args &&...args){
			return fun_(ref(*this), forward<Args>(args)...);
		}
	};
	template <typename Fun>
	decltype(auto) y_combinator(Fun &&fun){
		return y_combinator_result<decay_t<Fun>>(forward<Fun>(fun));
	}
};

void setIO(string s) // USACO
{
	#ifndef LOCAL
	    freopen((s + ".in").c_str(), "r", stdin);
	    freopen((s + ".out").c_str(), "w", stdout);
	#endif
}

struct TrackMedian{
	multiset<int> low, high;
	ll sumLow{}, sumHigh{};
	void add(int x) {
		if (sz(low) == 0) {
			sumLow += x;
			low.insert(x);
			return;
		}
		if (x > *low.rbegin()) {
			high.insert(x);
			sumHigh += x;
			if (sz(high) > sz(low)) {
				sumHigh -= *high.begin();
				sumLow += *high.begin();
				low.insert(*high.begin()), high.erase(high.begin());
			}
		}else{
			low.insert(x);
			sumLow += x;
			if (sz(high) + 1 < sz(low)) {
				sumHigh += *low.rbegin();
				sumLow -= *low.rbegin();
				high.insert(*low.rbegin());
				low.erase(--low.end());
			}
		}
	}
	void remove(int x) {
		if (x > *low.rbegin()) {
			high.erase(high.find(x));
			sumHigh -= x;
			if (sz(high) + 1 < sz(low)) {
				sumHigh += *low.rbegin();
				sumLow -= *low.rbegin();
				high.insert(*low.rbegin());
				low.erase(--low.end());
			}
		}else{
			low.erase(low.find(x));
			sumLow -= x;
			if (sz(high) > sz(low)) {
				sumHigh -= *high.begin();
				sumLow += *high.begin();
				low.insert(*high.begin()), high.erase(high.begin());
			}
		}
	}
	ll calc() {
		if (!sz(low)) return 0LL;
		int med = *low.rbegin();
		return sumHigh - 1LL * med * sz(high) + 1LL * med * sz(low) - sumLow;
	}
};

void solve()
{
	int k, n;
	cin >> k >> n;
	ll ans{};
	ll extra = LINF;
	vi order;
	vpi a;
	F0R(i, n) {
		char c, d;
		int l, r;
		cin >> c >> l >> d >> r;
		if (c != d)	order.pb(l), order.pb(r), a.pb({l, r}), ans++;
		else ans += abs(r - l);
	}
	if (k == 1) {
		sort(all(order));
		if (sz(order)) {
			int med = order[sz(order) / 2];
			for (auto &[l, r] : a) ans += abs(l - med) + abs(r - med);
		}
		cout << ans;
	}else{
		sort(all(a), [&](pii p, pii q) {
			return (p.fi + p.se) < (q.fi + q.se);
		});
		TrackMedian lo, hi;
		for (auto &[l, r] : a) hi.add(l), hi.add(r);
		ckmin(extra, hi.calc());
		F0R(i, sz(a)) {
			hi.remove(a[i].fi), hi.remove(a[i].se);
			lo.add(a[i].fi), lo.add(a[i].se);
			while (i + 1 < sz(a) && (a[i + 1].fi + a[i + 1].se) == a[i].fi + a[i].se) {
				i++;
				hi.remove(a[i].fi), hi.remove(a[i].se);
				lo.add(a[i].fi), lo.add(a[i].se);
			}
			ckmin(extra, hi.calc() + lo.calc());
		}
		cout << ans + extra;
	}
}

int main()
{
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);
    int testcase=1;
    // cin >> testcase;
    while (testcase--)
    {
        solve();
    }
}

Compilation message (stderr)

bridge.cpp: In function 'void setIO(std::string)':
bridge.cpp:94:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |      freopen((s + ".in").c_str(), "r", stdin);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
bridge.cpp:95:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   95 |      freopen((s + ".out").c_str(), "w", stdout);
      |      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 14 / 14
• Subtask 3: 9 / 9
• Subtask 4: 32 / 32
• Subtask 5: 37 / 37