oj.uz

Submission #146323

# Submission time Handle Problem Language Result Execution time Memory
146323 2019-08-23T13:11:43 Z evpipis Pipes (CEOI15_pipes) C++
100 / 100
 1908 ms 15972 KB 
#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define pb push_back
#define mp make_pair
typedef pair<int, int> ii;

const int len = 1e5+3;
int n, m, cnt;
int par[len], num[len], low[len];
vector<ii> adj[len], vec;

struct dsu{
    int anc[len];

    void init(){
        for (int i = 1; i <= n; i++)
            anc[i] = i;
    }

    int fin(int i){
        if (anc[i] == i) return i;
        return anc[i] = fin(anc[i]);
    }

    void join(int i, int j){
        i = fin(i), j = fin(j);
        if (i != j)
            anc[j] = i;
    }
};

dsu one, two;

void dfs(int u){
    num[u] = low[u] = ++cnt;
    for (int j = 0; j < adj[u].size(); j++){
        ii v = adj[u][j];
        if (!num[v.fi]){
            par[v.fi] = v.se;
            dfs(v.fi);

            if (low[v.fi] > num[u])
                printf("%d %d\n", u, v.fi);
            low[u] = min(low[u], low[v.fi]);
        }
        else if (v.se != par[u]){
            low[u] = min(low[u], num[v.fi]);
        }
    }
}

int main(){
    scanf("%d %d", &n, &m);
    one.init();
    two.init();
    for (int i = 0; i < m; i++){
        int a, b;
        scanf("%d %d", &a, &b);
        if (one.fin(a) != one.fin(b)){
            vec.pb(mp(a, b));
            one.join(a, b);
        }
        else if (two.fin(a) != two.fin(b)){
            vec.pb(mp(a, b));
            two.join(a, b);
        }
    }

    for (int i = 0; i < vec.size(); i++){
        int a = vec[i].fi, b = vec[i].se;
        adj[a].pb(mp(b, i+1));
        adj[b].pb(mp(a, i+1));
    }

    for (int i = 1; i <= n; i++)
        if (!num[i])
            dfs(i);
    return 0;
}

Compilation message

pipes.cpp: In function 'void dfs(int)':
pipes.cpp:39:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int j = 0; j < adj[u].size(); j++){
                     ~~^~~~~~~~~~~~~~~
pipes.cpp: In function 'int main()':
pipes.cpp:72:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < vec.size(); i++){
                     ~~^~~~~~~~~~~~
pipes.cpp:56:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~~
pipes.cpp:61:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &a, &b);
         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 2680 KB Output is correct
2 Correct 4 ms 2680 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 3320 KB Output is correct
2 Correct 9 ms 3064 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 143 ms 3136 KB Output is correct
2 Correct 140 ms 3064 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 249 ms 3984 KB Output is correct
2 Correct 288 ms 4980 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 420 ms 5840 KB Output is correct
2 Correct 377 ms 5484 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 605 ms 12144 KB Output is correct
2 Correct 516 ms 9828 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 916 ms 13436 KB Output is correct
2 Correct 929 ms 10284 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1274 ms 15972 KB Output is correct
2 Correct 1139 ms 12776 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1508 ms 15972 KB Output is correct
2 Correct 1436 ms 12900 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1813 ms 15400 KB Output is correct
2 Correct 1908 ms 12332 KB Output is correct