oj.uz

Submission #223368

# Submission time Handle Problem Language Result Execution time Memory
223368 2020-04-15T08:11:27 Z jamielim Matching (COCI20_matching) C++14
18 / 110
 33 ms 30200 KB 
#include <bits/stdc++.h>
using namespace std;

int n;
pair<int,int> arr[100005];
pair<int,int> adj[2][100005];
vector<int> al[100005];

struct node{
	int s,e,m,v;
	node *l,*r;
	node(int S,int E){
		s=S;e=E;m=(s+e)/2;v=0;
		if(s!=e){l=new node(s,m);r=new node(m+1,e);}
	}
	void upd(int x,int add){
		if(s==e){v+=add;return;}
		if(x<=m)l->upd(x,add);
		else r->upd(x,add);
		v=l->v+r->v;
	}
	int qry(int x,int y){
		if(s==x&&e==y)return v;
		if(y<=m)return l->qry(x,y);
		if(x>m)return r->qry(x,y);
		return l->qry(x,m)+r->qry(m+1,y);
	}
}*root;

bool poss(vector<pair<int,int> > v){
	//check whether the connections here intersect (false) or not (true)
	vector<pair<int,int> > hor,ver[100005];
	for(int i=0;i<(int)v.size();i++){
		if(arr[v[i].first].first==arr[v[i].second].first){
			ver[arr[v[i].first].first].push_back(make_pair(arr[v[i].first].second,arr[v[i].second].second));
		}else{
			int a=arr[v[i].first].first,b=arr[v[i].second].first;
			if(a>b)swap(a,b);
			hor.push_back(make_pair(a,arr[v[i].first].second));hor.push_back(make_pair(b,-arr[v[i].second].second));
		}
	}
	sort(hor.begin(),hor.end());
	set<int> s[100005];
	root=new node(0,100005);
	int ptr=0;
	for(int i=0;i<100005;i++){
		while(ptr<(int)hor.size()&&hor[ptr].first<=i){
			if(hor[ptr].second>0)root->upd(hor[ptr].second,1);
			else root->upd(-hor[ptr].second,-1);
			ptr++;
		}
		for(int j=0;j<(int)ver[i].size();j++){
			int a=ver[i][j].first,b=ver[i][j].second;
			if(a>b)swap(a,b);
			if(root->qry(a,b)>0){
				return false;
			}
		}
	}
	return true;
}

int main(){
	scanf("%d",&n);
	for(int i=0;i<100005;i++)adj[0][i]=adj[1][i]=make_pair(-1,-1);
	for(int i=0;i<n;i++){
		scanf("%d%d",&arr[i].first,&arr[i].second);
		if(adj[0][arr[i].first].first==-1)adj[0][arr[i].first].first=i;
		else adj[0][arr[i].first].second=i;
		if(adj[1][arr[i].second].first==-1)adj[1][arr[i].second].first=i;
		else adj[1][arr[i].second].second=i;
	}
	for(int i=0;i<n;i++){
		if(adj[0][arr[i].first].second==-1&&adj[1][arr[i].second].second==-1){
			printf("NE");return 0;
		}
		if(adj[0][arr[i].first].second!=-1){
			if(adj[0][arr[i].first].first==i)al[i].push_back(adj[0][arr[i].first].second);
			else al[i].push_back(adj[0][arr[i].first].first);
		}
		if(adj[1][arr[i].second].second!=-1){
			if(adj[1][arr[i].second].first==i)al[i].push_back(adj[1][arr[i].second].second);
			else al[i].push_back(adj[1][arr[i].second].first);
		}
	}
	//for(int i=0;i<n;i++){for(int j=0;j<(int)al[i].size();j++)printf("%d ",al[i][j]);printf("\n");}
	vector<pair<int,int> > ans;
	queue<int> q;
	for(int i=0;i<n;i++){
		if((int)al[i].size()==1)q.push(i);
	}
	while(!q.empty()){
		int cur=q.front();q.pop();
		for(int i=0;i<(int)al[cur].size();i++){
			int x=al[cur][i];
			if((int)al[x].size()==2){
				if(al[x][0]==cur){
					al[x][0]=al[x][1];
				}
				al[x].pop_back();
				q.push(x);
				ans.push_back(make_pair(cur,x));
			}else if((int)al[x].size()==1){
				al[x].clear();
				ans.push_back(make_pair(cur,x));
			}
		}
		al[cur].clear();
	}
	//for(int i=0;i<n;i++){for(int j=0;j<(int)al[i].size();j++)printf("%d ",al[i][j]);printf("\n");}
	//everything left in al is degree 2, connect these in one direction
	vector<pair<int,int> > ans2;for(int i=0;i<(int)ans.size();i++)ans2.push_back(ans[i]);
	//ans is vertical, ans2 is horizontal. need to check whether things intersect at the end
	for(int i=0;i<n;i++){
		if((int)al[i].size()==0)continue;
		assert((int)al[i].size()==2);
		if(arr[al[i][0]].first==arr[i].first&&al[i][0]<i){
			ans.push_back(make_pair(al[i][0],i));
		}else if(arr[al[i][1]].first==arr[i].first&&al[i][1]<i){
			ans.push_back(make_pair(al[i][1],i));
		}
		if(arr[al[i][0]].second==arr[i].second&&al[i][0]<i){
			ans2.push_back(make_pair(al[i][0],i));
		}else if(arr[al[i][1]].second==arr[i].second&&al[i][1]<i){
			ans2.push_back(make_pair(al[i][1],i));
		}
	}
	if(poss(ans)){
		printf("DA\n");
		for(int i=0;i<(int)ans.size();i++){
			printf("%d %d\n",ans[i].first+1,ans[i].second+1);
		}
	}else if(poss(ans2)){
		printf("DA\n");
		for(int i=0;i<(int)ans2.size();i++){
			printf("%d %d\n",ans2[i].first+1,ans2[i].second+1);
		}
	}else{
		printf("NE");
	}
}

Compilation message

matching.cpp: In function 'int main()':
matching.cpp:64:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
matching.cpp:67:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&arr[i].first,&arr[i].second);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 20736 KB Output is correct
2 Correct 21 ms 20736 KB Output is correct

Subtask #2
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 20736 KB Output is correct
2 Correct 21 ms 20736 KB Output is correct
3 Correct 21 ms 20608 KB Output is correct
4 Correct 20 ms 20736 KB Output is correct
5 Correct 21 ms 20640 KB Output is correct
6 Correct 32 ms 30076 KB Output is correct
7 Correct 32 ms 30080 KB Output is correct

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 20736 KB Output is correct
2 Correct 21 ms 20736 KB Output is correct
3 Correct 21 ms 20608 KB Output is correct
4 Correct 20 ms 20736 KB Output is correct
5 Correct 21 ms 20640 KB Output is correct
6 Correct 32 ms 30076 KB Output is correct
7 Correct 32 ms 30080 KB Output is correct
8 Correct 23 ms 20728 KB Output is correct
9 Correct 33 ms 30080 KB Output is correct
10 Correct 32 ms 30080 KB Output is correct
11 Correct 32 ms 30080 KB Output is correct
12 Correct 21 ms 20736 KB Output is correct

Subtask #4
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 20736 KB Output is correct
2 Correct 21 ms 20736 KB Output is correct
3 Correct 21 ms 20608 KB Output is correct
4 Correct 20 ms 20736 KB Output is correct
5 Correct 21 ms 20640 KB Output is correct
6 Correct 32 ms 30076 KB Output is correct
7 Correct 32 ms 30080 KB Output is correct
8 Correct 23 ms 20728 KB Output is correct
9 Correct 33 ms 30080 KB Output is correct
10 Correct 32 ms 30080 KB Output is correct
11 Correct 32 ms 30080 KB Output is correct
12 Correct 21 ms 20736 KB Output is correct
13 Incorrect 33 ms 30200 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #5
0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 20736 KB Output is correct
2 Correct 21 ms 20736 KB Output is correct
3 Correct 21 ms 20608 KB Output is correct
4 Correct 20 ms 20736 KB Output is correct
5 Correct 21 ms 20640 KB Output is correct
6 Correct 32 ms 30076 KB Output is correct
7 Correct 32 ms 30080 KB Output is correct
8 Correct 23 ms 20728 KB Output is correct
9 Correct 33 ms 30080 KB Output is correct
10 Correct 32 ms 30080 KB Output is correct
11 Correct 32 ms 30080 KB Output is correct
12 Correct 21 ms 20736 KB Output is correct
13 Incorrect 33 ms 30200 KB Output isn't correct
14 Halted 0 ms 0 KB -