Submission #1476252

---

Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define e1 first
#define e2 second
#define pb push_back
#define mp make_pair
#define boost {ios_base::sync_with_stdio(false);}
#define eb emplace_back
#define OUT(x) {cout << x; exit(0); }
#define FOR(i, a, b) for(int i=(a); i<=(b); ++i)
#define scanf(...) scanf(__VA_ARGS__)?:0
typedef long long ll;
typedef unsigned long long ull;
typedef pair <int, int> PII;
typedef pair <ll, ll> PLL;
typedef pair <PII, PII> PP;
typedef pair <PII, int> PPI;
typedef pair <int, PII> PIP;
typedef pair <ll, int> PLI;
typedef unsigned int ui;
typedef vector <int> vi;
const int mod = 1e9+7;
const int inf = 1e9+10;
const ll MOD = 1e9+696969;
const ll INF = 1e18;
const int W = 1e9;
#define maxn 20100
PII t[maxn];
int skladowa[maxn], x[maxn], n, m, a, b, c;
bool odw[maxn];
inline bool odl(int p, int q) {
	return abs(p - q);
}
set <PII> q;
vector <int> top;
int Key;

inline void topdfs(int u) {
	odw[u] = 1;
	while (1)
	{
		set <PII> :: iterator it = q.lower_bound(mp(x[u] - Key + 1, -inf));
		while (it != q.end() && (it->e2 == u || abs(((*it).e2 - u) == n)))++it;
		if (it == q.end()) break;
		if (abs(x[u] - x[it -> e2]) >= Key) break;
		PII tmp = *it;
		q.erase(it);
		//cout << "Znalazlem krawedz: " << u << ' ' << tmp.e2 << endl;
		if (tmp.e2 > n && !odw[tmp.e2 - n]) topdfs(tmp.e2 - n);
		else if (tmp.e2 <= n && !odw[tmp.e2 + n]) topdfs(tmp.e2 + n);
	}	
	top.pb(u);
}
 
inline void ccdfs(int u, int skl) {
	odw[u] = 1;
	skladowa[u] = skl;
	int para = (u <= n)?u+n:u-n;
	while (1)
	{
		set <PII> :: iterator it = q.lower_bound(mp(x[para] - Key + 1, -inf));
		while (it != q.end() && (it->e2 == u || it->e2 == para)) ++it;
		if (it == q.end()) break;
		if (abs(x[para] - x[it -> e2]) >= Key) break;
		PII tmp = *it;
		q.erase(it);
		//cout << "Znalazlem na odwrot: " << para << ' ' << tmp.e2 << endl;
		if (!odw[tmp.e2]) ccdfs(tmp.e2, skl);
	}
}

inline bool check(int k)
{
	Key = k;
	int N = 2 * n;
	FOR(i, 1, N) odw[i] = 0;
	q.clear();
	FOR(i, 1, n)
	{
		q.insert(mp(t[i].e1, i));
		q.insert(mp(t[i].e2, i + n));
	}
	top.clear();
	
	int SKL = 0;
	FOR(i, 1, N)
		if (!odw[i]) topdfs(i);
		
	assert((int)top.size() == N);
	
	FOR(i, 1, N) skladowa[i] = 0, odw[i] = 0;
	q.clear();
	FOR(i, 1, n)
	{
		q.insert(mp(t[i].e1, i));
		q.insert(mp(t[i].e2, i + n));
	}
	
	for (int i=(int)top.size()-1; i>=0; --i)
		if (!odw[top[i]])
		{
			++SKL;
			ccdfs(top[i], SKL);
		}
	
	FOR(i, 1, n)
		if (skladowa[i] == skladowa[i + n]) return 0;
	
	return 1;
}
 
int main()
{
	boost;
	cin >> n;
	FOR(i, 1, n) 
	{
		cin >> t[i].e1 >> t[i].e2;
		x[i + n] = t[i].e2;
		x[i] = t[i].e1;
	}
	
	int fx = 0, fy = inf;
	while (fx < fy) 
	{
		int sr = (fx + fy)/2+1;
		if (!check(sr)) fy = --sr;
		else fx = sr;
	}
	
	cout << fx;
}

Submission Info

Judge Result