oj.uz

Submission #830847

# Submission time Handle Problem Language Result Execution time Memory
830847 2023-08-19T11:33:14 Z TB_ Network (BOI15_net) C++17
100 / 100
 394 ms 90924 KB 
#include <bits/stdc++.h>
using namespace std;

// #undef _GLIBCXX_DEBUG                // disable run-time bound checking, etc
// #pragma GCC optimize("Ofast,inline") // Ofast = O3,fast-math,allow-store-data-races,no-protect-parens
// #pragma GCC optimize ("unroll-loops")

// #pragma GCC target("bmi,bmi2,lzcnt,popcnt")                      // bit manipulation
// #pragma GCC target("movbe")                                      // byte swap
// #pragma GCC target("aes,pclmul,rdrnd")                           // encryption
// #pragma GCC target("avx,avx2,f16c,fma,sse3,ssse3,sse4.1,sse4.2") // SIMD

// #include <bits/extc++.h>
// using namespace __gnu_pbds;
// template<class T>using ordered_set = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
// template<class T>using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define ll long long
#define INF (ll)1e9+7
#define fo(i, n) for(ll i=0;i<((ll)n);i++)
#define deb(x) cout << #x << " = " << x << endl;
#define deb2(x, y) cout << #x << " = " << x << ", " << #y << " = " << y << endl
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define LSOne(S) ((S) & (-S))
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
inline int readint(){ int v = 0; char c; while((c = getchar()) != EOF && c != ' ' && c != '\n'){ v *= 10; v += c - '0'; } return v; }
inline int readintsigned() { int v = 0; int sign = 1; char c = getchar(); if (c == '-') { sign = -1; } else { v += c - '0'; } while ((c = getchar()) != EOF && c != ' ' && c != '\n') { v *= 10; v += c - '0'; } return v * sign; }
inline string readstring() { string s; char c; while ((c = getchar()) != EOF && c != '\n' && c != ' ') { s.push_back(c); } return s; }
template <class result_t=std::chrono::milliseconds,class clock_t=std::chrono::steady_clock,class duration_t = std::chrono::milliseconds>
auto since(std::chrono::time_point<clock_t, duration_t> const& start){return std::chrono::duration_cast<result_t>(clock_t::now() - start);}
typedef pair<int, int> pii;
typedef pair<ll, ll> pl;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpii;
typedef vector<pl> vpl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<vpii> vvpii;
typedef vector<vpl> vvpl;

vpl ans;
vvl adj(500001);
pl dfs(int u, int last = -1){
    if(adj[u].size() == 1) return {u, -1};
    pl res = {-1, -1};
    for(auto v : adj[u]){
        if(v == last) continue;
        pl t_res = dfs(v, u);
        if(res.S == -1) swap(res, t_res);
        if(t_res.F == -1) continue;
        if(res.S != -1){
            ans.pb({res.S, t_res.F});
            res.S = t_res.S;
        } else res.S = t_res.F;
    }
    return res;
}

int main() {
    // cout << fixed << setprecision(20);
    // auto start = std::chrono::steady_clock::now(); // since(start).count()
    cin.tie(0)->sync_with_stdio(0);

    int n, from, to, start = 0;
    cin >> n;
    vi degree(n, 0);
    fo(i, n-1){
        cin >> from >> to;
        degree[--from]++;
        degree[--to]++;
        adj[from].pb(to);
        adj[to].pb(from);
    }
    fo(i, n) if(degree[i] > 1) start = i;
    
    pl res = dfs(start);
    if(res.S != -1) ans.pb(res);
    else ans.pb({res.F, start});

    cout << ans.size() << "\n";
    fo(i, ans.size()) cout << ans[i].F+1 << " " << ans[i].S+1 << "\n";

    return 0;
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 11988 KB Output is correct
2 Correct 7 ms 11988 KB Output is correct
3 Correct 7 ms 12008 KB Output is correct
4 Correct 8 ms 12116 KB Output is correct
5 Correct 6 ms 11988 KB Output is correct
6 Correct 6 ms 11988 KB Output is correct
7 Correct 6 ms 11988 KB Output is correct
8 Correct 6 ms 12004 KB Output is correct
9 Correct 7 ms 11988 KB Output is correct
10 Correct 6 ms 11988 KB Output is correct
11 Correct 6 ms 11988 KB Output is correct
12 Correct 7 ms 11988 KB Output is correct
13 Correct 6 ms 11988 KB Output is correct
14 Correct 7 ms 12016 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 11988 KB Output is correct
18 Correct 6 ms 11996 KB Output is correct
19 Correct 8 ms 11988 KB Output is correct
20 Correct 6 ms 11988 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 11988 KB Output is correct
2 Correct 7 ms 11988 KB Output is correct
3 Correct 7 ms 12008 KB Output is correct
4 Correct 8 ms 12116 KB Output is correct
5 Correct 6 ms 11988 KB Output is correct
6 Correct 6 ms 11988 KB Output is correct
7 Correct 6 ms 11988 KB Output is correct
8 Correct 6 ms 12004 KB Output is correct
9 Correct 7 ms 11988 KB Output is correct
10 Correct 6 ms 11988 KB Output is correct
11 Correct 6 ms 11988 KB Output is correct
12 Correct 7 ms 11988 KB Output is correct
13 Correct 6 ms 11988 KB Output is correct
14 Correct 7 ms 12016 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 11988 KB Output is correct
18 Correct 6 ms 11996 KB Output is correct
19 Correct 8 ms 11988 KB Output is correct
20 Correct 6 ms 11988 KB Output is correct
21 Correct 6 ms 12052 KB Output is correct
22 Correct 8 ms 12212 KB Output is correct
23 Correct 7 ms 12212 KB Output is correct
24 Correct 7 ms 12136 KB Output is correct
25 Correct 6 ms 12188 KB Output is correct
26 Correct 6 ms 12080 KB Output is correct
27 Correct 7 ms 12116 KB Output is correct
28 Correct 7 ms 12084 KB Output is correct
29 Correct 6 ms 12076 KB Output is correct
30 Correct 6 ms 11988 KB Output is correct
31 Correct 7 ms 12152 KB Output is correct
32 Correct 6 ms 11952 KB Output is correct
33 Correct 7 ms 11988 KB Output is correct
34 Correct 6 ms 12056 KB Output is correct
35 Correct 6 ms 11988 KB Output is correct
36 Correct 7 ms 12028 KB Output is correct
37 Correct 6 ms 12116 KB Output is correct
38 Correct 6 ms 12116 KB Output is correct
39 Correct 6 ms 11988 KB Output is correct
40 Correct 8 ms 11988 KB Output is correct
41 Correct 6 ms 11988 KB Output is correct
42 Correct 6 ms 12072 KB Output is correct
43 Correct 6 ms 12116 KB Output is correct
44 Correct 6 ms 11988 KB Output is correct
45 Correct 7 ms 12076 KB Output is correct
46 Correct 6 ms 12080 KB Output is correct
47 Correct 6 ms 11988 KB Output is correct
48 Correct 6 ms 11988 KB Output is correct
49 Correct 6 ms 12124 KB Output is correct
50 Correct 6 ms 12072 KB Output is correct
51 Correct 7 ms 11988 KB Output is correct
52 Correct 6 ms 11988 KB Output is correct
53 Correct 7 ms 12080 KB Output is correct
54 Correct 7 ms 11988 KB Output is correct
55 Correct 6 ms 11988 KB Output is correct
56 Correct 7 ms 12076 KB Output is correct
57 Correct 7 ms 12076 KB Output is correct
58 Correct 11 ms 12148 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 11988 KB Output is correct
2 Correct 7 ms 11988 KB Output is correct
3 Correct 7 ms 12008 KB Output is correct
4 Correct 8 ms 12116 KB Output is correct
5 Correct 6 ms 11988 KB Output is correct
6 Correct 6 ms 11988 KB Output is correct
7 Correct 6 ms 11988 KB Output is correct
8 Correct 6 ms 12004 KB Output is correct
9 Correct 7 ms 11988 KB Output is correct
10 Correct 6 ms 11988 KB Output is correct
11 Correct 6 ms 11988 KB Output is correct
12 Correct 7 ms 11988 KB Output is correct
13 Correct 6 ms 11988 KB Output is correct
14 Correct 7 ms 12016 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 11988 KB Output is correct
18 Correct 6 ms 11996 KB Output is correct
19 Correct 8 ms 11988 KB Output is correct
20 Correct 6 ms 11988 KB Output is correct
21 Correct 6 ms 12052 KB Output is correct
22 Correct 8 ms 12212 KB Output is correct
23 Correct 7 ms 12212 KB Output is correct
24 Correct 7 ms 12136 KB Output is correct
25 Correct 6 ms 12188 KB Output is correct
26 Correct 6 ms 12080 KB Output is correct
27 Correct 7 ms 12116 KB Output is correct
28 Correct 7 ms 12084 KB Output is correct
29 Correct 6 ms 12076 KB Output is correct
30 Correct 6 ms 11988 KB Output is correct
31 Correct 7 ms 12152 KB Output is correct
32 Correct 6 ms 11952 KB Output is correct
33 Correct 7 ms 11988 KB Output is correct
34 Correct 6 ms 12056 KB Output is correct
35 Correct 6 ms 11988 KB Output is correct
36 Correct 7 ms 12028 KB Output is correct
37 Correct 6 ms 12116 KB Output is correct
38 Correct 6 ms 12116 KB Output is correct
39 Correct 6 ms 11988 KB Output is correct
40 Correct 8 ms 11988 KB Output is correct
41 Correct 6 ms 11988 KB Output is correct
42 Correct 6 ms 12072 KB Output is correct
43 Correct 6 ms 12116 KB Output is correct
44 Correct 6 ms 11988 KB Output is correct
45 Correct 7 ms 12076 KB Output is correct
46 Correct 6 ms 12080 KB Output is correct
47 Correct 6 ms 11988 KB Output is correct
48 Correct 6 ms 11988 KB Output is correct
49 Correct 6 ms 12124 KB Output is correct
50 Correct 6 ms 12072 KB Output is correct
51 Correct 7 ms 11988 KB Output is correct
52 Correct 6 ms 11988 KB Output is correct
53 Correct 7 ms 12080 KB Output is correct
54 Correct 7 ms 11988 KB Output is correct
55 Correct 6 ms 11988 KB Output is correct
56 Correct 7 ms 12076 KB Output is correct
57 Correct 7 ms 12076 KB Output is correct
58 Correct 11 ms 12148 KB Output is correct
59 Correct 279 ms 42240 KB Output is correct
60 Correct 319 ms 45352 KB Output is correct
61 Correct 8 ms 11988 KB Output is correct
62 Correct 6 ms 11988 KB Output is correct
63 Correct 225 ms 38284 KB Output is correct
64 Correct 8 ms 12628 KB Output is correct
65 Correct 14 ms 14804 KB Output is correct
66 Correct 81 ms 32720 KB Output is correct
67 Correct 394 ms 90924 KB Output is correct
68 Correct 390 ms 74412 KB Output is correct
69 Correct 11 ms 13140 KB Output is correct
70 Correct 55 ms 23880 KB Output is correct
71 Correct 210 ms 47664 KB Output is correct
72 Correct 219 ms 46188 KB Output is correct
73 Correct 54 ms 20564 KB Output is correct
74 Correct 320 ms 43020 KB Output is correct
75 Correct 21 ms 15820 KB Output is correct
76 Correct 217 ms 47256 KB Output is correct
77 Correct 219 ms 47520 KB Output is correct
78 Correct 23 ms 16980 KB Output is correct
79 Correct 361 ms 61272 KB Output is correct
80 Correct 7 ms 12244 KB Output is correct
81 Correct 72 ms 23288 KB Output is correct
82 Correct 254 ms 45188 KB Output is correct
83 Correct 356 ms 43056 KB Output is correct
84 Correct 319 ms 43104 KB Output is correct
85 Correct 326 ms 43084 KB Output is correct
86 Correct 323 ms 45360 KB Output is correct
87 Correct 296 ms 45404 KB Output is correct