Submission #1160753

#	Time	Username	Problem	Language	Result	Execution time	Memory
1160753		TIN	Domino (COCI15_domino)	C++17	70 / 160	4104 ms	589824 KiB

domino

#include <bits/stdc++.h>

using namespace std;

#define FNAME "test"

template<typename T> inline bool minimize(T& _a, T _b) { return _a > _b ? _a = _b, true : false; };
template<typename T> using min_heap = priority_queue<T, vector<T>, greater<T>>;

typedef long long ll;

struct MCMF {
	using F = ll;
	using C = ll;

	struct Edge {
		int to;
		F flow, cap;
		C cost;

		Edge() {}

		Edge(int to, F flow, F cap, C cost) : to(to), flow(flow), cap(cap), cost(cost) {}
	};

	int N, M;
	vector<C> p, dist;
	vector<int> pre;
	vector<Edge> edges;
	vector<vector<int>> adj;

	void init(int _N) {
		N = _N; M = 0;
		p.resize(N);
		dist.resize(N);
		pre.resize(N);
		adj.resize(N);
	}

	void add_edge(int u, int v, F cap, C cost) {
		assert(cap >= 0);
		adj[u].push_back(M++); edges.push_back(Edge(v, 0, cap, cost));
		adj[v].push_back(M++); edges.push_back(Edge(u, 0, 0, -cost));
	}

	bool find_min_cost_path(int s, int t) {
		const C oo = numeric_limits<C>::max();
		for (int i = 0; i < N; i++) dist[i] = oo;
		using T = pair<C,int>; min_heap<T> pq;
		pq.push(make_pair(dist[s] = 0, s));
		while (!pq.empty()) {
			T x = pq.top(); pq.pop();
			if (x.first > dist[x.second]) continue;
			for (int e_id : adj[x.second]) {
				const Edge& E = edges[e_id];
				if (E.flow < E.cap && minimize(dist[E.to], x.first + E.cost + p[x.second] - p[E.to])) {
					pre[E.to] = e_id;
					pq.push(make_pair(dist[E.to], E.to));
				}
			}
		}
		return dist[t] != oo;
	}

	pair<F,C> calc(int s, int t) {
		assert(s != t);
		for (int _ = 0; _ < N; _++) {
			for (int e_id = 0; e_id < M; e_id++) {
				const Edge& E = edges[e_id];
				if (E.cap) minimize(p[E.to], p[edges[e_id ^ 1].to] + E.cost);
			}
		}
		F totalFlow = 0;
		C totalCost = 0;
		while (find_min_cost_path(s, t)) {
			for (int i = 0; i < N; i++) p[i] += dist[i];
			F df = numeric_limits<F>::max();
			for (int x = t; x != s; x = edges[pre[x] ^ 1].to) {
				const Edge& E = edges[pre[x]];
				minimize(df, E.cap - E.flow);
			}
			totalFlow += df;
			totalCost += df * (p[t] - p[s]);
			for (int x = t; x != s; x = edges[pre[x] ^ 1].to) {
				edges[pre[x]].flow += df;
				edges[pre[x] ^ 1].flow -= df;
			}
		}
		return make_pair(totalFlow, totalCost);
	}
};

int n, k;
ll sum, ans;
MCMF MinCostMaxFlow;

void Task() {
	ios_base::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	cout << fixed << setprecision(9);
	if (fopen(FNAME".inp","r")) {
		freopen(FNAME".inp","r",stdin);
		freopen(FNAME".out","w",stdout);
	}
}

void Solve() {
	//Your Code
	cin >> n >> k;
	MinCostMaxFlow.init(n * n + 3);
	MinCostMaxFlow.add_edge(n * n + 2, 0, k, 0);
	sum = 0;
	for (int i  = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			ll x;
			cin >> x;
			sum += x;
			int id = (i - 1) * n + j;
			if ((i + j) % 2) {
				MinCostMaxFlow.add_edge(0, id, 1, -x);
				if (j != n) MinCostMaxFlow.add_edge(id, id + 1, 1, 0);
				if (i != n) MinCostMaxFlow.add_edge(id, id + n, 1, 0);
				if (j != 1) MinCostMaxFlow.add_edge(id, id - 1, 1, 0);
				if (i != 1) MinCostMaxFlow.add_edge(id, id - n, 1, 0);
			} else {
				MinCostMaxFlow.add_edge(id, n * n + 1, 1, -x);
			}
		}
	}
	cout << sum + MinCostMaxFlow.calc(n * n + 2, n * n + 1).second << '\n';
}

int main() {
	Task();
	Solve();
	cerr << "\nTime run: " << 1000*clock()/CLOCKS_PER_SEC << "ms";
	return 37^37;
}

Compilation message (stderr)

domino.cpp: In function 'void Task()':
domino.cpp:102:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  102 |                 freopen(FNAME".inp","r",stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
domino.cpp:103:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  103 |                 freopen(FNAME".out","w",stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 10 / 10
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• Subtask 4: 10 / 10
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• Subtask 8: 10 / 10
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• Subtask 10: 10 / 10
• Subtask 11: 10 / 10
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• Subtask 15: 10 / 10
• Subtask 16: 0 / 10