제출 #975763

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
975763		starchan	Port Facility (JOI17_port_facility)	C++17	0 / 100	9 ms	35672 KiB

port_facility

#include<bits/stdc++.h>
using namespace std;
#define in array<int, 2>
#define pb push_back
#define pob pop_back
#define fast() ios_base::sync_with_stdio(false); cin.tie(NULL)
 
const int SMX = 1e6+5;
const int MX = 2e6+3;
const int LMX = 3e7+5e6;
const int mod = 1e9+7;
 
vector<int> g[SMX];

int lleft[LMX];
int rright[LMX];
int tree[LMX];
int nxt = 0;
 
int New()
{
	nxt++;
	lleft[nxt] = rright[nxt] = -1;
	return nxt;
}
 
int build(int l, int r)
{
	int id = New(); int m = (l+r)/2;
	if(l==r)
		return id;
	lleft[id] = build(l, m); rright[id] = build(m+1, r);  tree[id] = 0;
	return id;
}
 
int upd(const int &i, int pos, int id, int l, int r)
{
	int id_n;
	if(l == r)
		id_n = i;
	else
		id_n = New();
	tree[id_n] = 1;
	if(l == r)
		return id_n;
	lleft[id_n] = lleft[id]; rright[id_n] = rright[id];
	int m = (l+r)/2;
	if(pos <= m)
		lleft[id_n] = upd(i, pos, lleft[id], l, m);
	else
		rright[id_n] = upd(i, pos, rright[id], m+1, r);
	return id_n;
}
 
void add(const int &pp, int ql, int qr, int id, int l, int r)
{
	if(qr < l || r < ql)
		return;
	if((ql <= l) && (r <= qr))
	{
		g[pp].pb(id);
		return;
	}
	int m = (l+r)/2;
	add(pp, ql, qr, lleft[id], l, m);
	add(pp, ql, qr, rright[id], m+1, r);
	return;
}
 
int pa[LMX]; bool col[LMX]; bool works = true;
 
int leader(int u)
{
	if(pa[u] < 0)
		return u;
	else
	{
		int p = leader(pa[u]);
		col[u] = col[u]^col[pa[u]];
		return pa[u] = p;
	}
}
 
void merge(int u, int v, int xr)
{
	int x = leader(u);
	int y = leader(v);
	if(x == y)
	{
		if(col[u]^col[v]^xr)
			works = false;
		return;
	}
	if(pa[x] < pa[y])
	{
		swap(x, y);
		swap(u, v);
	}
	pa[y]+=pa[x];
	pa[x] = y;
	col[x] = col[u]^col[v]^xr;
	return;
}
bitset<LMX> vis, ppl;
void dfs(int u)
{
	vis[u] = 1;
	if(lleft[u] != -1)
	{
		if((!vis[lleft[u]]) && tree[lleft[u]])
			dfs(lleft[u]);
		if((!vis[rright[u]]) && tree[rright[u]])
			dfs(rright[u]);
		if(tree[lleft[u]]){
		//cout << "cat_L_Calling " << lleft[u] << " from " << u << endl;
		merge(u, lleft[u], 0);}
		if(tree[rright[u]]){
		//cout << "cat_R_Calling " << rright[u] << " from " << u << endl;
		merge(u, rright[u], 0);}
		return;
	}
	for(int v: g[u])
	{
		if(!tree[v])
			continue;
		merge(u, v, 1);
		if(vis[v])
		{
			//cout << "Tried to call " << v << " from " << u << endl;
			continue;
		}
		//cout << "Calling " << v << " from " << u <<  "\n";
		dfs(v);
	}
	return;
}
 
signed main()
{
	fast();//During debugging, this should ideally be removed.
	int n;
	cin >> n;
	vector<in> vv(n);
	for(int i = 0; i < n; i++)
		cin >> vv[i][0] >> vv[i][1];
	sort(vv.begin()+1, vv.end());
	int sn = 0; nxt = n; int root = build(1, 2*n); //cout << "nxt = " << nxt << endl;
 
	int b[n];
	for(int i = 0; i < n; i++)
	{
		lleft[i] = rright[i] = -1;
		root = upd(i, vv[i][1], root, 1, 2*n);
		add(i, vv[i][0], vv[i][1]-1, root, 1, 2*n);
		//cout << "b[sn] = " << b[sn] << endl;
	}
 
	int N = nxt; 
	for(int i = 0; i <= N; i++)
		pa[i] = -1;
	for(int i = 0; i < n; i++)
		dfs(i);
	if(!works)
	{
		cout << "0\n";
		return 0;
	}
	int ans = 1;
	for(int i = 0; i < n; i++)
	{
		if(ppl[leader(i)])
			continue;
		ppl[leader(i)] = 1; ans*=2; ans%=mod;
	}
	cout << ans << "\n";
	return 0;
}	

컴파일 시 표준 에러 (stderr) 메시지

port_facility.cpp: In function 'int main()':
port_facility.cpp:147:6: warning: unused variable 'sn' [-Wunused-variable]
  147 |  int sn = 0; nxt = n; int root = build(1, 2*n); //cout << "nxt = " << nxt << endl;
      |      ^~
port_facility.cpp:149:6: warning: unused variable 'b' [-Wunused-variable]
  149 |  int b[n];
      |      ^

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