Submission #113632

#	Time	Username	Problem	Language	Result	Execution time	Memory
113632		aminra	Port Facility (JOI17_port_facility)	C++14	0 / 100	165 ms	196088 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const int MOD = (int)1e9 + 7;
const int MAXN = (int)2e6 + 3;
const int infint = (int)2e9;
const ll inf = (ll)2e18;
int a[MAXN], b[MAXN], id[MAXN], n, par[MAXN], sz;
int get(int u)
{
	return par[u] < 0 ? u : par[u] = get(par[u]);
}
void merge(int u, int v)
{
	if((u = get(u)) == (v = get(v)))
		return;
	sz--;
	if(par[u] > par[v])
		swap(u, v);
	par[u] += par[v];
	par[v] = u;
}
vector<int> seg[4 * MAXN];
bool cyc;
bool cmp(int u, int v)
{
	return a[u] < a[v];
}
void add(int node, int st, int en, int idx, int val)
{
	for (auto u : seg[node])
		merge(u, val);
	seg[node].clear();
	if(en - st < 2)
		return;
	int mid = (st + en) >> 1;
	if(idx < mid)
		add(node << 1, st, mid, idx, val);
	else
		add(node << 1 | 1, mid, en, idx, val);
	return;
}
void ask(int node, int st, int en, int l, int r, int val)
{
	if(l >= en || st >= r)
		return;
	if(l <= st && en <= r)
	{
		seg[node].push_back(val);
		return;
	}
	int mid = (st + en) >> 1;
	ask(node << 1, st, mid, l, r, val);
	ask(node << 1 | 1, mid, en, l, r, val);
	return;
}
int pwr(int a, int b)
{
	if(b == 0)
		return 1;
	int c = pwr(a, b >> 1);
	c = 1LL * c * c % MOD;
	if(b & 1)
		c = 1LL * c * a % MOD;
	return c;
}
map<int, int> pos;
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	cin >> n;
	sz = n;
	for (int i = 0; i < n; i++)
		cin >> a[i] >> b[i];
	memset(par, -1, sizeof par);
	for (int i = 0; i < n; i++)
		id[i] = i, a[i]--, b[i]--;
	sort(id, id + n, cmp);
	//check if there's odd cycle
	for (int i = 0; i < n; i++)
	{
        auto st = pos.lower_bound(a[id[i]]), ft = pos.lower_bound(b[id[i]]);
        while(st != ft)
		{
            merge(id[i], st -> second + n); 
			merge(id[i] + n, st -> second);
            if(get(st -> second) == get((--ft) -> second))
				break;
            ft++;
            st++;
        }
        pos[b[id[i]]] = i;
    }
    for (int i = 0; i < n; i++)
    	if(get(i) == get(i + n))
    		return cout << 0, 0;
    		
    sz = n;		
    memset(par, -1, sizeof par);
	for (int i = n - 1; i >= 0; i--)
	{
		add(1, 0, 2 * n, b[id[i]], id[i]);
		ask(1, 0, 2 * n, a[id[i]], b[id[i]] + 1, id[i]);
	}
	cout << pwr(2, sz);
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 56
• Subtask 4: 0 / 22