Submission #152690

#	Time	Username	Problem	Language	Result	Execution time	Memory
152690		toloraia	Pipes (CEOI15_pipes)	C++14	0 / 100	7 ms	2808 KiB

pipes

#include <bits/stdc++.h>
#define F first
#define S second
#define mp make_pair
#define pb push_back
#define ll long long
#define LEFT(a) ((a)<<1)
#define RIGHT(a) (LEFT(a) + 1)
#define MID(a,b) ((a+b)>>1)
#define MAX(a,b) ((a)>(b)?(a):(b))
#define MIN(a,b) ((a)<(b)?(a):(b))
//#pragma comment(linker, "/STACK: 20000000005")
#pragma GCC optimize("Ofast")
#pragma GCC target("avx2,fma")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
using namespace std;

const int N = 1e5 + 5;

int n, m;
int nn, u[N], v[N];

vector < int > g[N];

int T;
int in[N], up[N];

int x, y;

map < pair < int, int >, int > M;

void dfs (int k, int p){
    in[k] = ++T;
    up[k] = in[k];
    for (int to : g[k]){
        if (to == p)
            continue;
        if (in[to]){
            up[k] = min (up[k], in[to]);
            continue;
        }
        dfs (to, k);
        if (up[to] > in[k]){
            x = min (k, to);
            y = max (k, to);
            if (M[{x, y}] == 1){
                nn++;
                u[nn] = k;
                v[nn] = to;
            }
        }
        up[k] = min (up[k], up[to]);
    }
}


main()
{
    freopen ("in.in", "r", stdin);freopen ("out.out", "w", stdout);
    ios_base::sync_with_stdio(false);
    cin >> n >> m;
    for (int i = 1; i <= m; i++){
        cin >> x >> y;
        if (x > y)
            swap (x, y);
        ++M[{x, y}];
        if (M[{x, y}] > 1)
            continue;
        g[x].pb (y);
        g[y].pb (x);
    }
    for (int i = 1; i <= n; i++)
        if (in[i] == 0)
            dfs (i, 0);
    for (int i = 1; i <= nn; i++)
        cout << u[i] << " " << v[i] << endl;
    return 0;
}

Compilation message (stderr)

pipes.cpp:17:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("O3")
 
pipes.cpp:18:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("unroll-loops")
 
pipes.cpp:60:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main()
      ^
pipes.cpp: In function 'int main()':
pipes.cpp:62:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen ("in.in", "r", stdin);freopen ("out.out", "w", stdout);
     ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
pipes.cpp:62:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen ("in.in", "r", stdin);freopen ("out.out", "w", stdout);
                                   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 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