Submission #1381124

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

struct Edge {
	int from, to;
	Edge(int f, int t) : from(f), to(t) {}
};

using Edges = vector<Edge>;
using Graph = vector<Edges>;

vector<int> tarjan(const Graph& g) {
	int n = g.size(), idx = 0, k = 0, s = 0;
	vector<int>ord(n, -1), low(n), onS(n), cmp(n), stk(n);
	function<void(int)> dfs = [&](int v) {
		ord[v] = low[v] = idx++;
		stk[s++] = v;
		onS[v] = true;
		for (auto &e : g[v]) {
			int w = e.to;
			if (ord[w] == -1) {
				dfs(w);
				low[v] = min(low[v], low[w]);
			}
			else if (onS[w]) {
				low[v] = min(low[v], ord[w]);
			}
		}
		if (low[v] == ord[v]) {
			while (1) {
				int w = stk[--s];
				onS[w] = false;
				cmp[w] = k;
				if (w == v)break;
			}
			++k;
		}
	};
	for (int v = 0; v<n; ++v)
		if (ord[v] == -1)dfs(v);
	return cmp;
}

int main()
{
	int N;
	cin >> N;
	vector<int> x(N), y(N);
	for (int i = 0; i < N; i++) {
		cin >> x[i] >> y[i];
	}
	int l = 0, r = 1e9 + 1;
	while (l + 1 < r) {
		int c = l + (r - l) / 2;
		Graph g(N * 2);
		for (int i = 0; i < N; i++) {
			for (int j = i + 1; j < N; j++) {
				if (abs(x[i] - x[j]) < c) {
					g[i].emplace_back(i, N + j);
					g[j].emplace_back(j, N + i);
				}
				if (abs(x[i] - y[j]) < c) {
					g[i].emplace_back(i, j);
					g[N + j].emplace_back(N + j, N + i);
				}
				if (abs(y[i] - x[j]) < c) {
					g[N + i].emplace_back(N + i, N + j);
					g[j].emplace_back(j, i);
				}
				if (abs(y[i] - y[j]) < c) {
					g[N + i].emplace_back(N + i, j);
					g[N + j].emplace_back(N + j, i);
				}
			}
		}
		auto v = tarjan(g);
		bool can = true;
		for (int i = 0; i < N; i++) {
			if (v[i] == v[i + N]) {
				can = false;
			}
		}
		if (can) {
			l = c;
		}
		else {
			r = c;
		}
	}
	cout << l << endl;
	return 0;
}

Submission Info

Judge Result