oj.uz

답안 #1045467

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1045467 2024-08-06T02:06:20 Z moonrabbit2 Parking (CEOI22_parking) C++17
100 / 100
 332 ms 42348 KB 
#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...)
#endif
using pii=array<int,2>;
const int N=200005;
int n,m,b[N],t[N];
vector<int> g[N],up[N],l[N];
bool vis[N];
vector<int> V,e;
bool ok=true,isCyc;
int outcnt;
vector<pii> ans;
vector<vector<int>> cycles;
void fail(){
	cout<<"-1\n";
	exit(0);
}
void upd(int i){
	vector<int> nl;
	for(int c: l[i]) if(b[c]==i||t[c]==i) nl.push_back(c);
	sort(nl.begin(),nl.end());
	nl.resize(unique(nl.begin(),nl.end())-nl.begin());
	for(int c: l[i]) if(b[c]==t[c]) nl.push_back(c);
	l[i]=nl;
	up[i].clear();
	for(int c: l[i]) if(b[c]==i&&t[c]) up[i].push_back(t[c]);
	g[i].clear();
	for(int c: l[i]) if(b[c]&&t[c]){
		if(b[c]!=i) g[i].push_back(b[c]);
		if(t[c]!=i) g[i].push_back(t[c]);
	}
}
void Do(int x,int y){
	assert(b[x]);
	if(t[x]){
		assert(!b[y]||t[x]==b[y]);
		if(!b[y]) b[y]=t[x];
		else t[y]=t[x];
		t[x]=0;
	} else{
		assert(!b[y]||b[x]==b[y]);
		if(!b[y]) b[y]=b[x];
		else t[y]=b[x];
		b[x]=0;
	}
	if(b[x]) upd(b[x]);
	if(t[x]) upd(t[x]);
	if(b[y]) upd(b[y]);
	if(t[y]) upd(t[y]);
	ans.push_back({x,y});
}
bool chk(int i){
	int x=l[i][0],y=l[i][1];
	if(!t[x]&&!t[y]){
		return true;
	} else if(!!t[x]+!!t[y]==1){
		if(t[x]) swap(x,y);
		if(i==t[y]){
			return true;
		}
	}
	return false;
}
void dfs(int u){
	V.push_back(u);
	vis[u]=1;
	isCyc&=g[u].size()==2;
	if(up[u].size()==2) outcnt++;
	for(int v: g[u]) if(!vis[v]) dfs(v);
}
int findDown(int i){
	if(b[l[i][0]]==i) return l[i][0];
	return l[i][1];
}
int findUp(int i){
	if(t[l[i][0]]==i) return l[i][0];
	return l[i][1];
}
void solvePath(){
	if(e.empty()) fail();
	int s=0;
	for(int u: V) if(g[u].size()==1) s=u;
	for(int u: V) vis[u]=0;
	V.clear();
	dfs(s);
	assert(up[s].size()==1);
	for(int s=0;s<(int)V.size();){
		int e1=s,e2=0;
		while(up[V[e1]].size()==1) e1++;
		e2=e1+1;
		while(e2+1<(int)V.size()&&up[V[e2]].size()==1) e2++;
		int x=l[V[e1]][0],y=l[V[e1]][1];
		Do(x,e[0]);
		Do(y,e[0]);
		for(int i=e1-1;i>s;i--) Do(findUp(V[i]),findDown(V[i]));
		int x1=l[V[s]][0],y1=l[V[s]][1];
		Do(x1,y1);
		e[0]=x1;
		for(int i=e1+1;i<e2;i++) Do(findUp(V[i]),findDown(V[i]));
		if(e2==(int)V.size()-1) break;
		s=e2;
	}
	int i=V.back(),x=l[i][0],y=l[i][1];
	Do(x,y);
	e.push_back(x);
}
void solveCycle(){
	if(!outcnt){
		if(e.empty()) fail();
		int s=V[0],x=b[findUp(s)];
		V.clear();
		while(x!=s){
			V.push_back(x);
			x=b[findUp(x)];
		}
		x=findUp(s);
		Do(x,e[0]);
		for(int u: V) Do(findUp(u),findDown(u));
		Do(e[0],findDown(s));
		return;
	}
	if(outcnt==1){
		if(e.empty()) fail();
		int s=0,t=0;
		for(int u: V){
			if(up[u].size()==0) s=u;
			if(up[u].size()==2) t=u;
		}
		int x=l[s][0],y=l[s][1];
		Do(x,e[0]);
		Do(y,e[0]);
		for(int i=b[x],j;i!=t;i=j){
			j=b[findUp(i)];
			Do(findUp(i),findDown(i));
		}
		for(int i=b[y],j;i!=t;i=j){
			j=b[findUp(i)];
			Do(findUp(i),findDown(i));
		}
		x=l[t][0],y=l[t][1];
		Do(x,y);
		e[0]=x;
		return;
	}
	if(e.size()<=1) fail();
	int s=0;
	for(int u: V) if(up[u].size()==0) s=u;
	int emp=e.back();
	e.pop_back();
	int x=l[s][0],y=l[s][1];
	Do(x,emp);
	Do(y,emp);
	int i;
	for(int i=b[x],j;up[i].size()!=1;i=j){
		j=b[findUp(i)];
		Do(findUp(i),findDown(i));
	}
	for(int i=b[y],j;up[i].size()!=1;i=j){
		j=b[findUp(i)];
		Do(findUp(i),findDown(i));
	}
	for(int u: V){
		vis[u]=0;
		if(l[u][0]!=l[u][1]) s=u;
	}
	V.clear();
	dfs(s);
	solvePath();
}
int main(){
	//freopen("input.txt","r",stdin);
	//freopen("output.txt","w",stdout);
	ios::sync_with_stdio(false); cin.tie(0);
	cin>>n>>m;
	for(int i=1;i<=m;i++){
		cin>>b[i]>>t[i];
		if(b[i]!=t[i]) ok=false;
		if(b[i]){
			l[b[i]].push_back(i);
		}
		if(t[i]){
			l[t[i]].push_back(i);
			if(b[i]!=t[i]){
				up[b[i]].push_back(t[i]);
				g[b[i]].push_back(t[i]);
				g[t[i]].push_back(b[i]);
			}
		}
	}
	if(ok){
		cout<<"0\n";
		return 0;
	}
	if(n==m) fail();
	for(int i=1;i<=m;i++) if(!b[i]) e.push_back(i);
	queue<int> que;
	for(int i=1;i<=n;i++){
		int x=l[i][0],y=l[i][1];
		if(x==y){
			vis[i]=1;
			continue;
		}
		if(chk(i)){
			vis[i]=1;
			que.push(i);
		}
	}
	while(que.size()){
		int i=que.front(); que.pop();
		int x=l[i][0],y=l[i][1];
		if(!t[x]&&!t[y]){
			Do(y,x);
			t[x]=i;
			b[y]=0;
			e.push_back(y);
		} else{
			if(t[x]) swap(x,y);
			Do(y,x);
			t[x]=i;
			t[y]=0;
			if(!vis[b[y]]&&chk(b[y])){
				vis[b[y]]=1;
				que.push(b[y]);
			}
		}
	}
	for(int s=1;s<=n;s++) if(!vis[s]){
		V.clear();
		isCyc=true;
		outcnt=0;
		dfs(s);
		if(!isCyc) solvePath();
		else cycles.push_back(V);
	}
	for(vector<int> cyc: cycles){
		for(int u: cyc) vis[u]=0;
		V.clear();
		isCyc=true;
		outcnt=0;
		dfs(cyc[0]);
		solveCycle();
	}
	cout<<ans.size()<<"\n";
	for(auto [x,y]: ans) cout<<x<<" "<<y<<"\n";
	return 0;
}

Compilation message

Main.cpp: In function 'void solveCycle()':
Main.cpp:157:6: warning: unused variable 'i' [-Wunused-variable]
  157 |  int i;
      |      ^

Subtask #1
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 14680 KB Output is correct
2 Correct 2 ms 14684 KB Output is correct
3 Correct 2 ms 14684 KB Output is correct
4 Correct 2 ms 14684 KB Output is correct
5 Correct 2 ms 14684 KB Output is correct
6 Correct 2 ms 14684 KB Output is correct
7 Correct 3 ms 14684 KB Output is correct
8 Correct 2 ms 14684 KB Output is correct
9 Correct 2 ms 14680 KB Output is correct
10 Correct 2 ms 14680 KB Output is correct

Subtask #2
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 57 ms 26060 KB Output is correct
2 Correct 75 ms 28244 KB Output is correct
3 Correct 46 ms 23500 KB Output is correct
4 Correct 41 ms 22988 KB Output is correct
5 Correct 76 ms 28220 KB Output is correct

Subtask #3
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 14680 KB Output is correct
2 Correct 3 ms 14684 KB Output is correct
3 Correct 2 ms 14684 KB Output is correct
4 Correct 3 ms 14936 KB Output is correct
5 Correct 2 ms 14684 KB Output is correct
6 Correct 2 ms 14680 KB Output is correct
7 Correct 2 ms 14936 KB Output is correct
8 Correct 2 ms 14936 KB Output is correct
9 Correct 3 ms 14940 KB Output is correct

Subtask #4
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 14680 KB Output is correct
2 Correct 3 ms 14684 KB Output is correct
3 Correct 2 ms 14684 KB Output is correct
4 Correct 3 ms 14936 KB Output is correct
5 Correct 2 ms 14684 KB Output is correct
6 Correct 2 ms 14680 KB Output is correct
7 Correct 2 ms 14936 KB Output is correct
8 Correct 2 ms 14936 KB Output is correct
9 Correct 3 ms 14940 KB Output is correct
10 Correct 225 ms 42196 KB Output is correct
11 Correct 34 ms 24412 KB Output is correct
12 Correct 106 ms 36692 KB Output is correct
13 Correct 252 ms 42000 KB Output is correct
14 Correct 81 ms 35724 KB Output is correct
15 Correct 99 ms 35920 KB Output is correct
16 Correct 242 ms 41824 KB Output is correct
17 Correct 120 ms 36368 KB Output is correct
18 Correct 236 ms 42172 KB Output is correct

Subtask #5
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 14940 KB Output is correct
2 Correct 2 ms 14936 KB Output is correct
3 Correct 3 ms 14940 KB Output is correct
4 Correct 2 ms 14684 KB Output is correct
5 Correct 2 ms 14680 KB Output is correct
6 Correct 3 ms 14936 KB Output is correct
7 Correct 3 ms 14684 KB Output is correct
8 Correct 3 ms 14936 KB Output is correct
9 Correct 3 ms 14936 KB Output is correct
10 Correct 3 ms 14684 KB Output is correct
11 Correct 2 ms 14940 KB Output is correct
12 Correct 3 ms 14936 KB Output is correct
13 Correct 2 ms 14684 KB Output is correct
14 Correct 2 ms 14684 KB Output is correct
15 Correct 3 ms 14684 KB Output is correct
16 Correct 2 ms 14936 KB Output is correct
17 Correct 3 ms 14684 KB Output is correct
18 Correct 3 ms 14940 KB Output is correct
19 Correct 3 ms 14940 KB Output is correct
20 Correct 2 ms 14936 KB Output is correct
21 Correct 2 ms 14680 KB Output is correct
22 Correct 4 ms 14936 KB Output is correct
23 Correct 2 ms 14680 KB Output is correct
24 Correct 2 ms 14940 KB Output is correct

Subtask #6
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 14680 KB Output is correct
2 Correct 2 ms 14684 KB Output is correct
3 Correct 2 ms 14684 KB Output is correct
4 Correct 2 ms 14684 KB Output is correct
5 Correct 2 ms 14684 KB Output is correct
6 Correct 2 ms 14684 KB Output is correct
7 Correct 3 ms 14684 KB Output is correct
8 Correct 2 ms 14684 KB Output is correct
9 Correct 2 ms 14680 KB Output is correct
10 Correct 2 ms 14680 KB Output is correct
11 Correct 57 ms 26060 KB Output is correct
12 Correct 75 ms 28244 KB Output is correct
13 Correct 46 ms 23500 KB Output is correct
14 Correct 41 ms 22988 KB Output is correct
15 Correct 76 ms 28220 KB Output is correct
16 Correct 3 ms 14680 KB Output is correct
17 Correct 3 ms 14684 KB Output is correct
18 Correct 2 ms 14684 KB Output is correct
19 Correct 3 ms 14936 KB Output is correct
20 Correct 2 ms 14684 KB Output is correct
21 Correct 2 ms 14680 KB Output is correct
22 Correct 2 ms 14936 KB Output is correct
23 Correct 2 ms 14936 KB Output is correct
24 Correct 3 ms 14940 KB Output is correct
25 Correct 225 ms 42196 KB Output is correct
26 Correct 34 ms 24412 KB Output is correct
27 Correct 106 ms 36692 KB Output is correct
28 Correct 252 ms 42000 KB Output is correct
29 Correct 81 ms 35724 KB Output is correct
30 Correct 99 ms 35920 KB Output is correct
31 Correct 242 ms 41824 KB Output is correct
32 Correct 120 ms 36368 KB Output is correct
33 Correct 236 ms 42172 KB Output is correct
34 Correct 3 ms 14940 KB Output is correct
35 Correct 2 ms 14936 KB Output is correct
36 Correct 3 ms 14940 KB Output is correct
37 Correct 2 ms 14684 KB Output is correct
38 Correct 2 ms 14680 KB Output is correct
39 Correct 3 ms 14936 KB Output is correct
40 Correct 3 ms 14684 KB Output is correct
41 Correct 3 ms 14936 KB Output is correct
42 Correct 3 ms 14936 KB Output is correct
43 Correct 3 ms 14684 KB Output is correct
44 Correct 2 ms 14940 KB Output is correct
45 Correct 3 ms 14936 KB Output is correct
46 Correct 2 ms 14684 KB Output is correct
47 Correct 2 ms 14684 KB Output is correct
48 Correct 3 ms 14684 KB Output is correct
49 Correct 2 ms 14936 KB Output is correct
50 Correct 3 ms 14684 KB Output is correct
51 Correct 3 ms 14940 KB Output is correct
52 Correct 3 ms 14940 KB Output is correct
53 Correct 2 ms 14936 KB Output is correct
54 Correct 2 ms 14680 KB Output is correct
55 Correct 4 ms 14936 KB Output is correct
56 Correct 2 ms 14680 KB Output is correct
57 Correct 2 ms 14940 KB Output is correct
58 Correct 166 ms 38332 KB Output is correct
59 Correct 218 ms 40636 KB Output is correct
60 Correct 147 ms 35776 KB Output is correct
61 Correct 173 ms 39252 KB Output is correct
62 Correct 33 ms 24656 KB Output is correct
63 Correct 200 ms 40676 KB Output is correct
64 Correct 88 ms 35668 KB Output is correct
65 Correct 187 ms 39868 KB Output is correct
66 Correct 271 ms 40916 KB Output is correct
67 Correct 91 ms 36124 KB Output is correct
68 Correct 332 ms 42348 KB Output is correct
69 Correct 316 ms 41372 KB Output is correct
70 Correct 170 ms 35848 KB Output is correct
71 Correct 134 ms 35548 KB Output is correct
72 Correct 158 ms 36204 KB Output is correct
73 Correct 298 ms 41912 KB Output is correct
74 Correct 178 ms 35904 KB Output is correct
75 Correct 331 ms 41020 KB Output is correct
76 Correct 330 ms 41676 KB Output is correct
77 Correct 303 ms 40744 KB Output is correct
78 Correct 140 ms 35668 KB Output is correct
79 Correct 309 ms 40188 KB Output is correct
80 Correct 149 ms 36644 KB Output is correct
81 Correct 309 ms 41676 KB Output is correct