Submission #125247

#	Time	Username	Problem	Language	Result	Execution time	Memory
125247		eriksuenderhauf	Pipes (CEOI15_pipes)	C++11	30 / 100	512 ms	16544 KiB

pipes

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>
#define mem(a,v) memset((a), (v), sizeof (a))
#define enl printf("\n")
#define case(t) printf("Case #%d: ", (t))
#define ni(n) scanf("%d", &(n))
#define nl(n) scanf("%I64d", &(n))
#define nai(a, n) for (int i = 0; i < (n); i++) ni(a[i])
#define nal(a, n) for (int i = 0; i < (n); i++) nl(a[i])
#define pri(n) printf("%d\n", (n))
#define prl(n) printf("%I64d\n", (n))
#define pii pair<int, int>
#define pil pair<int, long long>
#define pll pair<long long, long long>
#define vii vector<pii>
#define vil vector<pil>
#define vll vector<pll>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef cc_hash_table<int,int,hash<int>> ht;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> oset;
const double pi = acos(-1);
const int MOD = 1e9 + 7;
const int INF = 1e9 + 7;
const int MAXN = 1e4 + 5;
const double eps = 1e-9;
vi adj[MAXN];
int lo[MAXN], disc[MAXN];
int cnt = 1;

void dfs(int u, int p) {
	disc[u] = lo[u] = cnt++;
	for (int v: adj[u]) {
		if (!disc[v]) {
			dfs(v, u);
			lo[u] = min(lo[u], lo[v]);
			if (lo[v] > disc[u]) {
				auto it = lower_bound(adj[u].begin(),adj[u].end(),v)+1;
				if (it == adj[u].end() || *it != v)
					printf("%d %d\n", u, v);
			}
		} else if (v != p)
			lo[u] = min(lo[u], disc[v]);
	}
}

int main() {
	int n, m;
	scanf("%d %d", &n, &m);
	for (int i = 0; i < m; i++) {
		int u, v;
		scanf("%d %d", &u, &v);
		adj[u].pb(v);
		adj[v].pb(u);
	}
	for (int i = 1; i <= n; i++)
		sort(adj[i].begin(), adj[i].end());
	for (int i = 1; i <= n; i++)
		if (!disc[i])
			dfs(i, 0);
    return 0;
}

Compilation message (stderr)

pipes.cpp: In function 'int main()':
pipes.cpp:59:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:62:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &u, &v);
   ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10