oj.uz

Submission #100499

# Submission time Handle Problem Language Result Execution time Memory
100499 2019-03-11T19:34:30 Z doowey Pipes (CEOI15_pipes) C++14
20 / 100
 1243 ms 14844 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

#define fi first
#define se second
#define mp make_pair
#define fastIO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);

const int N = (int)1e5 + 9;

struct DSU{
    int pi[N];
    int sz[N];
    int fin(int x){
        if(pi[x] == x)
            return x;
        return pi[x] = fin(pi[x]);
    }
    bool unite(int a, int b){
        a = fin(a);
        b = fin(b);
        if(a==b)
            return false;
        if(sz[a] > sz[b])
            swap(a, b);
        sz[b] += sz[a];
        pi[a] = b;
        return true;
    }
    void Init(){
        for(int i = 0 ;i  < N ; i ++ ){
            pi[i] = i;
            sz[i] = 1;
        }
    }
};

DSU A, B;

vector<int> T[N];

vector<pii> answ;

int tin[N];
int low[N];
int timer;

bool vis[N];

void bridge(int a, int b){
    if(a>b)
        swap(a, b);
    answ.push_back(mp(a,b));
}

void dfs(int node, int par){
    if(vis[node]){
        return;
    }
    vis[node] = true;
    tin[node] = timer ++ ;
    low[node] = tin[node];
    for(auto x : T[node]){
        if(x == par){
            continue;
        }
        if(vis[x]){
            low[node] = min(low[node], tin[x]);
        }
        else{
            dfs(x, node);
            low[node] = min(low[node], low[x]);
            if(tin[node] < low[x]){
                bridge(node, x);
            }
        }
    }
}



int main(){
    fastIO;
    A.Init();
    B.Init();
    int n, m;
    cin >> n >> m;
    int u, v;
    for(int i = 0 ; i < m ; i ++ ){
        cin >> u >> v;
        if(A.fin(u) ==A.fin(v)){
            if(B.fin(u) == B.fin(v)){
                continue;
            }
            B.unite(u,v);
        }
        else{
            A.unite(u,v);
        }
        T[u].push_back(v);
        T[v].push_back(u);
    }
    for(int i = 1; i <= n; i ++ )
        dfs(i,-1);
    bool ok;
    sort(answ.begin(), answ.end());
    for(int i = 0 ;i < answ.size(); i ++ ){
        ok = true;
        if(i>0 && answ[i] == answ[i-1]) ok = false;
        if(i+1<answ.size() && answ[i] == answ[i+1]) ok = false;

        if(ok)
            cout << answ[i].fi << " " << answ[i].se << "\n";
    }
    return 0;
}

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:111:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0 ;i < answ.size(); i ++ ){
                    ~~^~~~~~~~~~~~~
pipes.cpp:114:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if(i+1<answ.size() && answ[i] == answ[i+1]) ok = false;
            ~~~^~~~~~~~~~~~

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 4224 KB Output is correct
2 Incorrect 5 ms 4224 KB Wrong number of edges

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 4736 KB Output is correct
2 Incorrect 9 ms 4480 KB Wrong number of edges

Subtask #3
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 98 ms 4580 KB Output is correct
2 Incorrect 96 ms 4472 KB Wrong number of edges

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 161 ms 5332 KB Wrong number of edges
2 Halted 0 ms 0 KB -

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 285 ms 6776 KB Output is correct
2 Correct 240 ms 6388 KB Output is correct

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 388 ms 11768 KB Output is correct
2 Incorrect 344 ms 8312 KB Wrong number of edges

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 596 ms 12908 KB Output is correct
2 Incorrect 588 ms 9956 KB Wrong number of edges

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 875 ms 14832 KB Output is correct
2 Incorrect 776 ms 9988 KB Wrong number of edges

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 977 ms 14844 KB Output is correct
2 Incorrect 946 ms 9988 KB Wrong number of edges

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1217 ms 14372 KB Output is correct
2 Correct 1243 ms 11404 KB Output is correct