oj.uz

Submission #527352

# Submission time Handle Problem Language Result Execution time Memory
527352 2022-02-17T09:24:54 Z jamielim Pipes (CEOI15_pipes) C++14
20 / 100
 1434 ms 17580 KB 
#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define mp make_pair
#define pb emplace_back
#define ALL(x) x.begin(),x.end()
#define SZ(x) (int)x.size()
typedef long long ll;
typedef pair<int,int> ii;
typedef pair<ii,ii> i4;
const int MOD=1000000007;
const int INF=1012345678;
const ll LLINF=1012345678012345678LL;
const double PI=3.1415926536;
const double EPS=1e-14;

const int MAXN=100005;
int n,m;
int par[MAXN],par2[MAXN];
int root(int x){return par[x]=(par[x]==x?x:root(par[x]));}
int root2(int x){return par2[x]=(par2[x]==x?x:root2(par2[x]));}
vector<int> adj[MAXN]; // only stores at most 2*tree

bool vis[MAXN];
int p[MAXN],low[MAXN],dep[MAXN];
int ctr=1;
void dfs(int x){
	vis[x]=1;
	dep[x]=low[x]=ctr++;
	for(int i:adj[x]){
		if(!vis[i]){
			p[i]=x;
			dfs(i);
			if(low[i]>dep[x])printf("%d %d\n",x,i);
			low[x]=min(low[x],low[i]);
		}else if(i!=p[x])low[x]=min(low[x],dep[i]);
	}
}

int main(){
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++)par[i]=par2[i]=i;
	int a,b;
	for(int i=0;i<m;i++){
		scanf("%d%d",&a,&b);
		//if a,b are in different trees, merge the two trees
		int ra=root(a),rb=root(b);
		if(ra!=rb){
			par[ra]=rb;
			adj[a].pb(b);
			adj[b].pb(a);
			continue;
		}
		//otherwise, take note that later we have to get rid of the entire cycle
		int r2a=root2(a),r2b=root2(b);
		if(r2a!=r2b){
			par2[r2a]=par2[r2b];
			adj[a].pb(b);
			adj[b].pb(a);
		}
	}
	
	for(int i=1;i<=n;i++)if(!vis[i])dfs(i);
}

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:43:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |  scanf("%d%d",&n,&m);
      |  ~~~~~^~~~~~~~~~~~~~
pipes.cpp:47:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |   scanf("%d%d",&a,&b);
      |   ~~~~~^~~~~~~~~~~~~~

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2636 KB Output is correct
2 Incorrect 1 ms 2648 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 3172 KB Output is correct
2 Incorrect 6 ms 3048 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #3
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 133 ms 6828 KB Output is correct
2 Incorrect 112 ms 6620 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 211 ms 7792 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 365 ms 11128 KB Output is correct
2 Correct 335 ms 8900 KB Output is correct

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 454 ms 11320 KB Output is correct
2 Incorrect 387 ms 7972 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 729 ms 12756 KB Output is correct
2 Incorrect 672 ms 9824 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 982 ms 15712 KB Output is correct
2 Incorrect 911 ms 10692 KB Wrong number of edges
3 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 1136 ms 17580 KB Memory limit exceeded
2 Halted 0 ms 0 KB -

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1434 ms 15972 KB Output is correct
2 Correct 1378 ms 12228 KB Output is correct