제출 #872694

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
872694		Ghulam_Junaid	Pipes (CEOI15_pipes)	C++17	0 / 100	944 ms	50520 KiB

pipes

/*
#include <bits/stdc++.h>
using namespace std;

const int N = 1e4 + 3;
int n, m;
bool edge[N][N], vis[N];
vector<vector<int>> comps; 
vector<int> independent;

int main(){
	cin >> n >> m;

	for (int i=0; i<m; i++){
		int u, v;
		cin >> u >> v;

		edge[u][v] = 1;
		edge[v][u] = 1;
	}

	for (int sz = n; sz > 0; sz--){
		string s;
		for (int i=0; i<n-sz; i++)
			s += '0';
		for (int i=0; i<sz; i++)
			s += '1';

		do {
			bool done = 0;
			for (int i=0; i<n; i++){
				if (s[i] == '1' and vis[i+1]){
					done = 1;
					break;
				}
			}
			
			if (done)
				continue;

			for (int v = 1; v <= n; v++){
				for (int u = v + 1; u <= n; u++){
					if (s[v - 1] == '1' and s[u - 1] == '1' and edge[v][u])
						done = 1;
				}
			}

			if (done)
				continue;

			for (int i=0; i<n; i++){
				if (s[i] == '1'){
					independent.push_back(i+1);
					vis[i+1] = 1;
				}
			}
			comps.push_back(independent);
			independent.clear();
		} 
		while (next_permutation(s.begin(), s.end()));
	}

	cout << comps.size() << endl;
	for (auto x : comps){
		for (auto v : x)
			cout << v << " ";
		cout << endl;
	}
}
*/


/*
./a.out < input_000.txt > output_000.txt
./a.out < input_001.txt > output_001.txt
./a.out < input_002.txt > output_002.txt
./a.out < input_003.txt > output_003.txt
./a.out < input_005.txt > output_005.txt
./a.out < input_006.txt > output_006.txt
./a.out < input_007.txt > output_007.txt
./a.out < input_008.txt > output_008.txt
./a.out < input_009.txt > output_009.txt
*/

/*
#include <bits/stdc++.h>
using namespace std;

const int N = 1e4 + 3;
int n, m, deg[N];
vector<int> g[N], independent;
bool vis[N], bad[N];
vector<vector<int>> comps;

void dfs(int v){
	if (v == 0)
		return;

	independent.push_back(v);
	vis[v] = 1;

	for (int u:g[v]){
		bad[u] = 1;
		deg[u]--;
	}

	int mn_node = 0;
	for (int i=1; i<=n; i++){
		if (!vis[i] && !bad[i] && deg[mn_node] > deg[i]){
			mn_node = i;
		}
	}

	dfs(mn_node);
}

int main(){
	cin >> n >> m;

	deg[0] = 1e9;
	for (int i=0; i<m; i++){
		int u, v;
		cin >> u >> v;
	
		g[u].push_back(v);
		g[v].push_back(u);
		deg[v]++;
		deg[u]++;
	}

	while(1){

		int mn_node = 0;
		for (int i=1; i<=n; i++)
			if (!vis[i] && deg[mn_node] > deg[i])
				mn_node = i;

		if (mn_node == 0)
			break;

		for (int i=1; i<=n; i++)
			bad[i] = 0;
		independent.clear();

		dfs(mn_node);
		comps.push_back(independent);
	}	
	cout << comps.size() << endl;
	for (auto x : comps){
		for (auto v : x)
			cout << v << " ";
		cout << endl;
	}
}
*/

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 10;
int par1[N], par2[N], h[N], mnh[N];
bool vis[N];
vector<int> g[N];
vector<pair<int, int>> bridges;

int root1(int v){
    return (par1[v] == -1 ? v : par1[v] = root1(par1[v]));
}

int root2(int v){
    return (par2[v] == -1 ? v : par2[v] = root2(par2[v]));
}

void merge1(int u, int v){
    // cout << "merge1 : " << u << " " << v << endl;
    
    int r1 = root1(v);
    int r2 = root1(u);


    par1[r1] = r2;

    g[v].push_back(u);
    g[u].push_back(v);
}

void merge2(int u, int v){
    int r1 = root2(u);
    int r2 = root2(v);

    if (r1 == r2)
        return;

    par2[r1] = r2;

    g[v].push_back(u);
    g[u].push_back(v);
}

void dfs(int v, int p = -1){
    // cout << v << endl;
    vis[v] = 1;
    mnh[v] = h[v];
    for (int u : g[v]){
        // cout << v << " -- " << u << endl;
        if (vis[u]){
            if (u != p)
                mnh[v] = min(mnh[v], h[u]);
            continue;
        }

        h[u] = h[v] + 1;
        dfs(u, v);
        mnh[v] = min(mnh[v], mnh[u]);

        // cout << u << " : " << mnh[u] << endl;
        if (mnh[u] >= h[u])
            bridges.push_back({u, v});
    }
}

int main(){
    int n, m;
    scanf("%d %d", &n, &m);

    for (int i=1; i<=n; i++)
        par1[i] = par2[i] = -1;

    for (int i=0; i<m; i++){
        int u, v;
        scanf("%d %d", &u, &v);

        if (root1(u) == root1(v))
            merge2(u, v);
        else
            merge1(u, v);
    }

    for (int v = 1; v <= n; v++){
        if (!vis[v]){
            // cout << "---------------\n";
            dfs(v);
        }
    }

    for (auto [u, v] : bridges)
        printf("%d %d\n", u, v);
}

/*

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 10;
int par1[N], par2[N], h[N], mnh[N];
bool vis[N];
vector<int> g[N];
vector<pair<int, int>> bridges;

int root1(int v){
    return (par1[v] == -1 ? v : par1[v] = root1(par1[v]));
}

int root2(int v){
    return (par2[v] == -1 ? v : par2[v] = root2(par2[v]));
}

void merge1(int u, int v){    
    int r1 = root1(v);
    int r2 = root1(u);

    par1[r1] = r2;

    g[v].push_back(u);
    g[u].push_back(v);
}

void merge2(int u, int v){
    int r1 = root2(u);
    int r2 = root2(v);

    if (r1 == r2)
        return;

    par2[r1] = r2;

    g[v].push_back(u);
    g[u].push_back(v);
}

void dfs(int v, int p = -1){
    vis[v] = 1;
    mnh[v] = h[v];
    for (int u : g[v]){
        if (vis[u]){
            if (u != p)
                mnh[v] = min(mnh[v], h[u]);
            continue;
        }

        h[u] = h[v] + 1;
        dfs(u, v);
        mnh[v] = min(mnh[v], mnh[u]);

        if (mnh[u] >= h[u])
            bridges.push_back({u, v});
    }
}

int main(){
    int n, m;
    scanf("%d%d", &n, &m);

    for (int i=1; i<=n; i++)
        par1[i] = par2[i] = -1;

    for (int i=0; i<m; i++){
        int u, v;
        scanf("%d%d", &u, &v);

        if (root1(u) == root1(v))
            merge2(u, v);
        else
            merge1(u, v);
    }

    for (int v = 1; v <= n; v++)
        if (!vis[v])
            dfs(v);

    for (auto [u, v] : bridges)
        printf("%d %d\n", u, v);
}

*/

컴파일 시 표준 에러 (stderr) 메시지

pipes.cpp: In function 'int main()':
pipes.cpp:224:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  224 |     scanf("%d %d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:231:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  231 |         scanf("%d %d", &u, &v);
      |         ~~~~~^~~~~~~~~~~~~~~~~

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