oj.uz

답안 #156088

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
156088 2019-10-03T08:36:46 Z HungAnhGoldIBO2020 전압 (JOI14_voltage) C++14
0 / 100
 144 ms 17228 KB 
#include<iostream>
#include<vector>
#include<algorithm>
const int N=2e5+2;
using namespace std;
vector<int> adj[N];
int cnt[N][3],color[N],level[N],numno=0,ans=0;
vector<pair<int,int> > lis;
bool used[N];
bool dfs(int x,bool valid){
	bool scare=valid,cac;
	for(int i=0;i<adj[x].size();i++){
		if(!color[adj[x][i]]){
			color[adj[x][i]]=3-color[x];
			if(scare){
				scare=dfs(adj[x][i],scare);
			}
			else{
				cac=dfs(adj[x][i],scare);	
			}
		}
		else{
			if(color[adj[x][i]]!=3-color[x]){
				scare=false;
			}
		}
	}
	return scare;
}
void dfs1(int x,int p){
	bool first=true;
	for(int i=0;i<adj[x].size();i++){
		if(!used[adj[x][i]]){
			used[adj[x][i]]=true;
			level[adj[x][i]]=level[x]+1;
			dfs1(adj[x][i],x);
			cnt[x][0]+=cnt[adj[x][i]][0];
			cnt[x][1]+=cnt[adj[x][i]][1];
		}
		else{
			if(adj[x][i]==p){
				if(first){
					first=false;
					continue;
				}
			}
			if(level[adj[x][i]]>level[x]){
				continue;
			}
			if((level[x]-level[adj[x][i]])%2==0){
				numno++;
				cnt[x][0]++;
				cnt[adj[x][i]][0]--;
			}
			else{
				cnt[x][1]++;
				cnt[adj[x][i]][1]--;
			}
		}
	}
}
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	int n,m,i,j,k,root=0,cnt1=0;
	cin>>n>>m;
	for(i=1;i<=m;i++){
		cin>>j>>k;
		lis.push_back({min(j,k),max(j,k)});
		adj[j].push_back(k);
		adj[k].push_back(j);
	}
	sort(lis.begin(),lis.end());
	for(i=1;i<lis.size();i++){
		if(i>0&&lis[i].first==lis[i-1].first&&lis[i].second==lis[i-1].second){
			cnt1++;
			if(i==1){
				cnt1++;
			}
			else{
				if(lis[i-1].first!=lis[i-2].first||lis[i-1].second!=lis[i-2].second){
					cnt1++;
				}
			}
		}
	}
	bool cac;
	for(i=1;i<=n;i++){
		if(!color[i]){
			color[i]=1;
			cac=dfs(i,true);
			if(!cac){
				if(!root){
					root=i;
				}
				else{
					cout<<0;
					return 0;
				}
			}
		}
	}
	if(!root){
		cout<<m-cnt1;
		return 0;
	}
	used[root]=true;
	dfs1(root,root);
	if(numno==1){
		ans++;
	}
	for(i=1;i<=n;i++){
		if(i!=root&&used[i]&&cnt[i][0]==numno&&cnt[i][1]==0){
			ans++;
		}
	}
	cout<<ans;
}

Compilation message

voltage.cpp: In function 'bool dfs(int, bool)':
voltage.cpp:12:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<adj[x].size();i++){
              ~^~~~~~~~~~~~~~
voltage.cpp:11:19: warning: variable 'cac' set but not used [-Wunused-but-set-variable]
  bool scare=valid,cac;
                   ^~~
voltage.cpp: In function 'void dfs1(int, int)':
voltage.cpp:32:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<adj[x].size();i++){
              ~^~~~~~~~~~~~~~
voltage.cpp: In function 'int main()':
voltage.cpp:74:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=1;i<lis.size();i++){
          ~^~~~~~~~~~~

Subtask #1
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 7 ms 5116 KB Output is correct
2 Correct 6 ms 5112 KB Output is correct
3 Correct 7 ms 5112 KB Output is correct
4 Correct 7 ms 5112 KB Output is correct
5 Incorrect 7 ms 5112 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 57 ms 9800 KB Output is correct
2 Correct 85 ms 12136 KB Output is correct
3 Correct 75 ms 10316 KB Output is correct
4 Correct 101 ms 17228 KB Output is correct
5 Correct 13 ms 6008 KB Output is correct
6 Incorrect 79 ms 10856 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #3
0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 37 ms 9708 KB Output is correct
2 Correct 49 ms 14024 KB Output is correct
3 Correct 56 ms 14056 KB Output is correct
4 Correct 6 ms 4984 KB Output is correct
5 Correct 71 ms 13804 KB Output is correct
6 Correct 78 ms 9452 KB Output is correct
7 Incorrect 85 ms 11608 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #4
0 / 45.0

# 결과 실행 시간 메모리 Grader output
1 Correct 84 ms 11464 KB Output is correct
2 Correct 97 ms 14792 KB Output is correct
3 Correct 7 ms 5368 KB Output is correct
4 Correct 98 ms 15464 KB Output is correct
5 Correct 105 ms 16764 KB Output is correct
6 Correct 105 ms 15336 KB Output is correct
7 Incorrect 144 ms 13284 KB Output isn't correct
8 Halted 0 ms 0 KB -