oj.uz

Submission #710821

# Submission time Handle Problem Language Result Execution time Memory
710821 2023-03-15T21:05:48 Z noedit Network (BOI15_net) C++17
100 / 100
 643 ms 65612 KB 
#include <bits/stdc++.h>
#include <quadmath.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//#define sz(x) (int)x.size()
//#define sqr(x) x*x
//#pragma GCC optimize("-O3")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,sse4.1,sse4.2,popcnt,abm,mmx,avx,avx2,tune=native")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("no-stack-protector")
//#pragma GCC optimize("fast-math")
using namespace std;
//using namespace __gnu_pbds;
//
//#define int long long
////#define ld long double
//template <class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;

vector<vector<int> > g;

vector<int> pr;
vector<int> tin, tout;
vector<int> ls;
vector<int> ord;
vector<int> tin_ord;

int timer = 0;

void dfs(int v, int p)
{
    tin[v] = timer++;
    pr[v] = p;
    if (g[v].size() == 1){
        ls[v]++;
        tin_ord.push_back(tin[v]);
        ord.push_back(v);
    }
    for (auto&u : g[v])
    {
        if (u != p)
        {
            dfs(u, v);
            ls[v] += ls[u];
        }
    }
    tout[v] = timer++;
}

int root = 0;

int cock(int v, int p)
{
    for (auto& u : g[v])
    {
        if (u != p)
        {
            if (ls[u] > ls[root] / 2)
            {
                return cock(u, v);
            }
        }
    }
    return v;
}

void solve()
{
    int n;
    cin >> n;
    g.resize(n);
    pr.resize(n);
    ls.resize(n);
    tin.resize(n);
    tout.resize(n);
    for (int i = 0; i < n - 1; i++)
    {
        int x, y;
        cin >> x >> y;
        x--; y--;
        g[x].push_back(y);
        g[y].push_back(x);
    }

    for (int i = 0; i < n; i++)
        if (g[i].size() > 1)
        root = i;
    dfs(root, root);
    vector<int> ans(ls[root] + ls[root] % 2);
    vector<int> cur;
    int j = cock(root, root);
    int lt = lower_bound(tin_ord.begin(), tin_ord.end(), tin[j]) - tin_ord.begin();
    int rt = upper_bound(tin_ord.begin(), tin_ord.end(), tout[j]) - tin_ord.begin() - 1;
    int k = 0;
    int fist = -1;
    for (int i = 0; i < lt; i++)
    {
        ans[k] = ord[i];
        if (fist == -1) fist = ord[i];
        k += 2;
        if (k == ans.size()) k = 1;
    }
    for (int i = rt + 1; i < ord.size(); i++)
    {
        ans[k] = ord[i];
        if (fist == -1) fist = ord[i];
        k += 2;
        if (k == ans.size()) k = 1;
    }
    for (auto& u : g[j])
    {
        if (u != pr[j])
        {
            int l = lower_bound(tin_ord.begin(), tin_ord.end(), tin[u]) - tin_ord.begin();
            int r = upper_bound(tin_ord.begin(), tin_ord.end(), tout[u]) - tin_ord.begin() - 1;
            for (int i = l; i <= r; i++)
            {
                 ans[k] = ord[i];
        if (fist == -1) fist = ord[i];
                 k += 2;
                 if (k == ans.size()) k = 1;
            }
        }
    }
    if (ls[root] % 2 == 1)
    {
        ans[ans.size() - 1] = fist;
    }
    cout << ans.size() / 2 << endl;
    for (int i = 0; i < ans.size(); i += 2)
    {
        cout << ans[i] + 1 << ' ' << ans[i + 1] + 1 << endl;
    }
}
//
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t;
    t = 1;
    //cin >> t;
    while (t--)
    {
        solve();
    }
    cerr << endl << fixed << setprecision(3) << "Time execution: " << (double)clock() / CLOCKS_PER_SEC << endl;
    return 0;
}
//
//
/*
17 13
1 3 1 2 1 3 1 2 1 1 2 1 2 1 2 1 3
3 1 2 3 3 2 1 2 1 3 2 2 1
*/
/*
6 9
3 2 1 6 7 4
3 2 6 10 8 9 7 1 4
*/
/*
9 8
2 1 4 6 7 8 9 10 11
8 9 10 11 1 4 6 7
*/

Compilation message

net.cpp: In function 'void solve()':
net.cpp:102:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  102 |         if (k == ans.size()) k = 1;
      |             ~~^~~~~~~~~~~~~
net.cpp:104:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  104 |     for (int i = rt + 1; i < ord.size(); i++)
      |                          ~~^~~~~~~~~~~~
net.cpp:109:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |         if (k == ans.size()) k = 1;
      |             ~~^~~~~~~~~~~~~
net.cpp:122:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  122 |                  if (k == ans.size()) k = 1;
      |                      ~~^~~~~~~~~~~~~
net.cpp:131:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  131 |     for (int i = 0; i < ans.size(); i += 2)
      |                     ~~^~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 316 KB Output is correct
10 Correct 1 ms 320 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 1 ms 212 KB Output is correct
15 Correct 1 ms 324 KB Output is correct
16 Correct 1 ms 212 KB Output is correct
17 Correct 1 ms 212 KB Output is correct
18 Correct 1 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 316 KB Output is correct
10 Correct 1 ms 320 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 1 ms 212 KB Output is correct
15 Correct 1 ms 324 KB Output is correct
16 Correct 1 ms 212 KB Output is correct
17 Correct 1 ms 212 KB Output is correct
18 Correct 1 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 3 ms 468 KB Output is correct
23 Correct 3 ms 468 KB Output is correct
24 Correct 2 ms 460 KB Output is correct
25 Correct 2 ms 468 KB Output is correct
26 Correct 2 ms 468 KB Output is correct
27 Correct 2 ms 460 KB Output is correct
28 Correct 2 ms 468 KB Output is correct
29 Correct 2 ms 464 KB Output is correct
30 Correct 1 ms 212 KB Output is correct
31 Correct 3 ms 456 KB Output is correct
32 Correct 1 ms 212 KB Output is correct
33 Correct 1 ms 212 KB Output is correct
34 Correct 1 ms 256 KB Output is correct
35 Correct 1 ms 320 KB Output is correct
36 Correct 1 ms 212 KB Output is correct
37 Correct 1 ms 320 KB Output is correct
38 Correct 1 ms 340 KB Output is correct
39 Correct 1 ms 212 KB Output is correct
40 Correct 1 ms 324 KB Output is correct
41 Correct 1 ms 212 KB Output is correct
42 Correct 1 ms 340 KB Output is correct
43 Correct 2 ms 340 KB Output is correct
44 Correct 1 ms 320 KB Output is correct
45 Correct 1 ms 328 KB Output is correct
46 Correct 2 ms 324 KB Output is correct
47 Correct 1 ms 212 KB Output is correct
48 Correct 1 ms 340 KB Output is correct
49 Correct 2 ms 340 KB Output is correct
50 Correct 1 ms 212 KB Output is correct
51 Correct 1 ms 212 KB Output is correct
52 Correct 1 ms 344 KB Output is correct
53 Correct 1 ms 340 KB Output is correct
54 Correct 1 ms 320 KB Output is correct
55 Correct 1 ms 356 KB Output is correct
56 Correct 2 ms 320 KB Output is correct
57 Correct 1 ms 324 KB Output is correct
58 Correct 3 ms 468 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 316 KB Output is correct
10 Correct 1 ms 320 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 1 ms 212 KB Output is correct
15 Correct 1 ms 324 KB Output is correct
16 Correct 1 ms 212 KB Output is correct
17 Correct 1 ms 212 KB Output is correct
18 Correct 1 ms 212 KB Output is correct
19 Correct 1 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 3 ms 468 KB Output is correct
23 Correct 3 ms 468 KB Output is correct
24 Correct 2 ms 460 KB Output is correct
25 Correct 2 ms 468 KB Output is correct
26 Correct 2 ms 468 KB Output is correct
27 Correct 2 ms 460 KB Output is correct
28 Correct 2 ms 468 KB Output is correct
29 Correct 2 ms 464 KB Output is correct
30 Correct 1 ms 212 KB Output is correct
31 Correct 3 ms 456 KB Output is correct
32 Correct 1 ms 212 KB Output is correct
33 Correct 1 ms 212 KB Output is correct
34 Correct 1 ms 256 KB Output is correct
35 Correct 1 ms 320 KB Output is correct
36 Correct 1 ms 212 KB Output is correct
37 Correct 1 ms 320 KB Output is correct
38 Correct 1 ms 340 KB Output is correct
39 Correct 1 ms 212 KB Output is correct
40 Correct 1 ms 324 KB Output is correct
41 Correct 1 ms 212 KB Output is correct
42 Correct 1 ms 340 KB Output is correct
43 Correct 2 ms 340 KB Output is correct
44 Correct 1 ms 320 KB Output is correct
45 Correct 1 ms 328 KB Output is correct
46 Correct 2 ms 324 KB Output is correct
47 Correct 1 ms 212 KB Output is correct
48 Correct 1 ms 340 KB Output is correct
49 Correct 2 ms 340 KB Output is correct
50 Correct 1 ms 212 KB Output is correct
51 Correct 1 ms 212 KB Output is correct
52 Correct 1 ms 344 KB Output is correct
53 Correct 1 ms 340 KB Output is correct
54 Correct 1 ms 320 KB Output is correct
55 Correct 1 ms 356 KB Output is correct
56 Correct 2 ms 320 KB Output is correct
57 Correct 1 ms 324 KB Output is correct
58 Correct 3 ms 468 KB Output is correct
59 Correct 537 ms 44312 KB Output is correct
60 Correct 582 ms 49324 KB Output is correct
61 Correct 1 ms 320 KB Output is correct
62 Correct 1 ms 212 KB Output is correct
63 Correct 455 ms 40616 KB Output is correct
64 Correct 2 ms 852 KB Output is correct
65 Correct 10 ms 2900 KB Output is correct
66 Correct 123 ms 20432 KB Output is correct
67 Correct 426 ms 65612 KB Output is correct
68 Correct 473 ms 58852 KB Output is correct
69 Correct 15 ms 1868 KB Output is correct
70 Correct 167 ms 16804 KB Output is correct
71 Correct 607 ms 54996 KB Output is correct
72 Correct 643 ms 53580 KB Output is correct
73 Correct 112 ms 13440 KB Output is correct
74 Correct 528 ms 47596 KB Output is correct
75 Correct 52 ms 6004 KB Output is correct
76 Correct 582 ms 53084 KB Output is correct
77 Correct 589 ms 53368 KB Output is correct
78 Correct 31 ms 5840 KB Output is correct
79 Correct 430 ms 52868 KB Output is correct
80 Correct 4 ms 724 KB Output is correct
81 Correct 160 ms 17348 KB Output is correct
82 Correct 575 ms 50404 KB Output is correct
83 Correct 536 ms 47524 KB Output is correct
84 Correct 543 ms 47560 KB Output is correct
85 Correct 551 ms 47576 KB Output is correct
86 Correct 579 ms 49316 KB Output is correct
87 Correct 600 ms 49232 KB Output is correct