Submission #167280

#	Time	Username	Problem	Language	Result	Execution time	Memory
167280		mhy908	Pipes (CEOI15_pipes)	C++14	0 / 100	71 ms	65540 KiB

pipes

#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define F first
#define S second
using namespace std;
typedef long long LL;
typedef pair<int, int> pii;
typedef pair<LL, LL> pll;
struct UNION_FIND{
    int par[100010];
    UNION_FIND(){for(int i=1; i<=100000; i++)par[i]=i;}
    int findpar(int num){return num==par[num]?num:par[num]=findpar(par[num]);}
    void mergepar(int a, int b){par[findpar(a)]=findpar(b);}
    bool query(int a, int b){return findpar(a)==findpar(b);}
}uf1, uf2;
stack<int> link[100010];
int n, m;
int disc[100010], lowlink[100010], par[100010], t;
void dfs(int u)
{
	disc[u]=lowlink[u]=++t;
	bool temp=false;
	int m=link[u].size();
	for(int i=1; i<=m; i++){
        int v=link[u].top();
        link[u].pop();
		if(v==par[u]&&!temp)temp=true;
		else{
			if(!disc[v]){
				par[v]=u;
				dfs(v);
				if(lowlink[v]>disc[u])printf("%d %d\n", u, v);
				lowlink[u]=min(lowlink[u], lowlink[v]);
			}
			else lowlink[u]=min(lowlink[u], disc[v]);
		}
	}
}
int main()
{
    scanf("%d %d", &n, &m);
    for(int i=1; i<=m; i++){
        int u, v;
        scanf("%d %d", &u, &v);
        if(!uf1.query(u, v)){
            uf1.mergepar(u, v);
            link[u].push(v);
            link[v].push(u);
        }
        else if(!uf2.query(u, v)){
            uf2.mergepar(u, v);
            link[u].push(v);
            link[v].push(u);
        }
    }
    for(int i=1; i<=n; i++){
        if(!disc[i])dfs(i);
    }
}

Compilation message (stderr)

pipes.cpp: In function 'int main()':
pipes.cpp:42:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:45:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &u, &v);
         ~~~~~^~~~~~~~~~~~~~~~~

• 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