#include<bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//using namespace __gnu_pbds;
using namespace std;
typedef long double ld;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef vector<pl> vpl;
typedef vector<ld> vld;
typedef pair<ld, ld> pld;
//typedef tree<ll, null_type, less_equal<ll>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
template<typename T>
ostream &operator<<(ostream &os, vector<T> &a) {
os << "[";
for (int i = 0; i < ll(a.size()); i++) { os << a[i] << ((i != ll(a.size() - 1) ? " " : "")); }
os << "]\n";
return os;
}
#define all(x) x.begin(),x.end()
#define YES out("YES")
#define NO out("NO")
#define out(x){cout << x << "\n"; return;}
#define GLHF ios_base::sync_with_stdio(false); cin.tie(NULL)
#define print(x){for(auto ait:x) cout << ait << " "; cout << "\n";}
#define pb push_back
#define umap unordered_map
template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
is >> p.first >> p.second;
return is;
}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, pair<T1, T2> &p) {
os << "" << p.first << " " << p.second << "";
return os;
}
void usaco(string taskname) {
string fin = taskname + ".in";
string fout = taskname + ".out";
const char *FIN = fin.c_str();
const char *FOUT = fout.c_str();
freopen(FIN, "r", stdin);
freopen(FOUT, "w", stdout);
}
template<typename T>
void read(vector<T> &v) {
int n = v.size();
for (int i = 0; i < n; i++)
cin >> v[i];
}
template<typename T>
vector<T> UNQ(vector<T> a) {
vector<T> ans;
for (T t: a)
if (ans.empty() || t != ans.back())
ans.push_back(t);
return ans;
}
ll ceil(ll a, ll b) {
ll ans = a / b;
if (a % b)ans++;
return ans;
}
ld log(ld a, ld b) { return log(b) / log(a); }
ll power(ll base, ll exp, ll M = 1e18) {//(base^exp)%M
ll ans = 1;
while (exp) {
if (exp % 2 == 1)ans = ((ans % M) * (base % M)) % M;
base = ((base % M) * (base % M)) % M;
exp /= 2;
}
return ans;
}
string to_base(int n, int new_base) {
string s;
int nn = n;
while (nn) {
s += to_string(nn % new_base);
nn /= new_base;
}
reverse(all(s));
return s;
}
ll gcd(ll a, ll b) {
if (a < b)swap(a, b);
if (b == 0)return a;
return gcd(b, a % b);
}
ll lcm(ll a, ll b) {
ll x = (a / gcd(a, b));
return b * x;
}
vl generate_array(ll n, ll mn = 1, ll mx = 1e18 + 1) {
if (mx == 1e18 + 1)
mx = n;
vl ans(n);
for (int i = 0; i < n; i++)
ans[i] = (mn + rand() % (mx - mn + 1));
return ans;
}
string substr(string s, int l, int r) {
string ans;
for (int i = l; i <= r; i++)
ans += s[i];
return ans;
}
void solve();
int main() {
GLHF;
int t = 1;
//cin >> t;
while (t--)
solve();
}
struct dsu{
vi par;
dsu(int n){
par.resize(n+1);
for(int i=1; i<=n; i++)
par[i]=i;
}
int get(int x){return par[x]=(x==par[x]?x:get(par[x]));}
void unite(int u,int v){
u=get(u),v=get(v);
if(u==v)
return;
par[u]=v;
}
};
vvi g;
vi low,dep;
vector<bool>vis;
set<pi>ans;
void dfs(int src,int par){
vis[src]=1;
if(par!=-1)
dep[src]=low[src]=dep[par]+1;
else
low[src]=dep[src]=0;
for(int nbr:g[src]){
if(nbr==par)
continue;
if(vis[nbr])
low[src]=min(low[src],dep[nbr]);
else
dfs(nbr,src),low[src]=min(low[src],low[nbr]);
}
if(dep[src]==low[src] && par!=-1)
ans.insert({src,par});
}
void solve() {
int n,m;
cin >> n >> m;
g.resize(n+1);
dsu d1(n),d2(n);
while(m--){
int u,v;
cin >> u >> v;
if(d1.get(u)!=d1.get(v)){
g[u].pb(v);
g[v].pb(u);
d1.unite(u,v);
}
else if(d2.get(u)!=d2.get(v)){
g[v].pb(u);
g[u].pb(v);
d2.unite(u,v);
}
}
vis.resize(n+1);
dep.resize(n+1);
low.resize(n+1,1e9);
for(int i=1; i<=n; i++)
if(!vis[i])
dfs(i,-1);
for(pi p:ans)
cout << p << "\n";
}
Compilation message
pipes.cpp: In function 'void usaco(std::string)':
pipes.cpp:56:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
56 | freopen(FIN, "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:57:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
57 | freopen(FOUT, "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
1 ms |
204 KB |
Output is correct |
| 2 |
Incorrect |
1 ms |
204 KB |
Wrong number of edges |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
5 ms |
960 KB |
Output is correct |
| 2 |
Incorrect |
5 ms |
716 KB |
Wrong number of edges |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
131 ms |
1476 KB |
Output is correct |
| 2 |
Incorrect |
152 ms |
936 KB |
Wrong number of edges |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
230 ms |
2408 KB |
Wrong number of edges |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
393 ms |
4292 KB |
Output is correct |
| 2 |
Correct |
332 ms |
11212 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
566 ms |
26300 KB |
Memory limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
871 ms |
41344 KB |
Memory limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
1166 ms |
55156 KB |
Memory limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
1436 ms |
65536 KB |
Memory limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Runtime error |
1810 ms |
65536 KB |
Memory limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
