Submission #213371

#	Time	Username	Problem	Language	Result	Execution time	Memory
213371		Saboon	Matching (COCI20_matching)	C++14	58 / 110	665 ms	524288 KiB

matching

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int maxn = 100000 + 10;
const int maxl = 80;

struct point{
	int x, y;
} p[maxn];

struct segment{
	point a;
	point b;
	int i1, i2;
	segment(){
		i1 = i2 = -1;
	}
} s[maxn];

vector<int> vex[maxn], vey[maxn], vec[maxn], add[maxn], del[maxn];
int ask[maxn], cnt;
int lc[maxn * maxl], rc[maxn * maxl];
vector<int> g[maxn * maxl][2];
bool light[maxn][2];
int cmp[maxn * maxl], comp;
bool visited[maxn * maxl];

vector<int> topol;
void dfs(int v, bool w){
	visited[v] = 1;
	for (auto u : g[v][w])
		if (!visited[u])
			dfs(u, w);
	if (w == 0)
		topol.push_back(v);
	else
		cmp[v] = comp;
}

void scc(){
	int n = cnt;
	for (int i = 0; i < n; i++)
		if (!visited[i])
			dfs(i, 0);
	reverse(topol.begin(), topol.end());
	memset(visited, 0, sizeof visited);
	for (auto i : topol){
		if (!visited[i]){
			dfs(i, 1);
			comp ++;
		}
	}
}

void add_edge(int v, int u, bool type){ // type = 0 : v -> u, else v <- u
	if (type == 1)
		swap(v, u);
//	cout << "edge : " << v << " -> " << u << endl;
	g[v][0].push_back(u);
	g[u][1].push_back(v);
}

void get(int id, int L, int R, int l, int r, int v, bool type){
	if (r <= L or R <= l)
		return;
	if (l <= L and R <= r){
		add_edge(v, id, type);
		return;
	}
	int mid = (L + R) >> 1;
	get(lc[id], L, mid, l, r, v, type);
	get(rc[id], mid, R, l, r, v, type);
}

int change(int id, int L, int R, int idx, int v, bool type){
	if (idx < L or R <= idx)
		return id;
	int me = cnt ++;
	if (L + 1 == R){
		if (light[L][type] == 1)
			return me;
		add_edge(me, v, type);
		light[L][type] = 1;
		return me;
	}
	int mid = (L + R) >> 1;
	lc[me] = change(lc[id], L, mid, idx, v, type);
	rc[me] = change(rc[id], mid, R, idx, v, type);
	add_edge(me, lc[me], type), add_edge(me, rc[me], type);
	return me;
}

int build(int L, int R, bool type){
	int me = cnt ++;
	if (L + 1 == R)
		return me;
	int mid = (L + R) >> 1;
	lc[me] = build(L, mid, type);
	rc[me] = build(mid, R, type);
	add_edge(me, lc[me], type), add_edge(me, rc[me], type);
	return me;
}

int main(){
	ios_base::sync_with_stdio(false);
	int n;
	cin >> n;
	for (int i = 0; i < n; i++){
		cin >> p[i].x >> p[i].y;
		vex[p[i].x].push_back(i);
		vey[p[i].y].push_back(i);
	}
	int newint = 0;
	int N = 100000 + 1;
	for (int i = 1; i < N; i++){
		if (vex[i].size() == 2){
			segment me;
			me.a = p[vex[i][0]];
			me.b = p[vex[i][1]];
			me.i1 = vex[i][0];
			me.i2 = vex[i][1];
			vec[me.i1].push_back(newint);
			vec[me.i2].push_back(newint);
			s[newint++] = me;
		}
		if (vey[i].size() == 2){
			segment me;
			me.a = p[vey[i][0]];
			me.b = p[vey[i][1]];
			me.i1 = vey[i][0];
			me.i2 = vey[i][1];
			vec[me.i1].push_back(newint);
			vec[me.i2].push_back(newint);
			s[newint++] = me;
		}
	}
	int m = newint;
	memset(ask, -1, sizeof ask);
	for (int i = 0; i < m; i++){
		if (s[i].a.x != s[i].b.x){
			if (s[i].a.x > s[i].b.x){
				swap(s[i].a, s[i].b);
				swap(s[i].i1, s[i].i2);
			}
			add[s[i].a.x].push_back(i);
			add[s[i].b.x].push_back(i);
		}
		else
			ask[s[i].a.x] = i;
	}
	for (int i = 0; i < n; i++){
		if ((int)vec[i].size() == 0)
			return cout << "NE\n", 0;
		if ((int)vec[i].size() == 1){
			int v = vec[i][0];
			add_edge(2*v+1, 2*v+0, 0);
			continue;
		}
		int v = vec[i][0], u = vec[i][1];
		add_edge(2*v+1, 2*u+0, 0);
		add_edge(2*u+1, 2*v+0, 0);
		add_edge(2*v+0, 2*u+1, 0);
		add_edge(2*u+0, 2*v+1, 0);
	}
//	for (int i = 0; i < m; i++)
//		cout << "# " << i << " -> (" << s[i].a.x << " , " << s[i].a.y << ") - (" << s[i].b.x << " , " << s[i].b.y << ")" << endl; 
	cnt = 2*m;
	int r1 = build(1, N, 0);
	int r2 = build(1, N, 1);
	for (int i = 1; i < N; i++){
		if (ask[i] != -1){
			int idx = ask[i];
			int y1 = s[idx].a.y, y2 = s[idx].b.y;
			if (y1 > y2)
				swap(y1, y2);
			get(r1, 1, N, y1+1, y2, 2*idx+0, 0);
			get(r2, 1, N, y1+1, y2, 2*idx+1, 1);
//			cout << "Ask : " << idx << " : " << y1+1 << " - " << y2 << endl;
		}
		for (auto idx : add[i]){
//			cout << "Add or Remove : " << idx << " - " << s[idx].a.y << endl;
			r1 = change(r1, 1, N, s[idx].a.y, 2*idx+1, 0);
			r2 = change(r2, 1, N, s[idx].a.y, 2*idx+0, 1);
		}
	}
	scc();
	for (int i = 0; i < 2*m; i+=2)
		if (cmp[i] == cmp[i+1])
			return cout << "NE\n", 0;
	cout << "DA\n";
	for (int i = 0; i < m; i++)
		if (cmp[2*i+0] > cmp[2*i+1])
			cout << s[i].i1 + 1 << " " << s[i].i2 + 1 << '\n';
}

• Subtask 1: 5 / 5
• Subtask 2: 6 / 6
• Subtask 3: 7 / 7
• Subtask 4: 40 / 40
• Subtask 5: 0 / 52