oj.uz

Submission #394659

# Submission time Handle Problem Language Result Execution time Memory
394659 2021-04-27T07:03:45 Z erfanmir Network (BOI15_net) C++17
100 / 100
 534 ms 45444 KB 
// In the name of god

#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 

using namespace std;
using namespace __gnu_pbds; 

template < class T > using ordered_set = tree < T , null_type , less < T > , rb_tree_tag , tree_order_statistics_node_update >;
  
typedef long long                   ll;
typedef long double                 ld;
typedef pair<int,int>               pii;
typedef pair<ll,ll>                 pll;
#define all(x)                      (x).begin(),(x).end()
#define lc(x)                       (x) << 1
#define rc(x)                       (x) << 1 | 1
#define F                           first
#define S                           second
#define fast_io                     ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io                     freopen("in.txt" , "r+" , stdin) ; freopen("out.txt" , "w+" , stdout);
#define mp                          make_pair
ll poww(ll a, ll b, ll md) {
    ll ans = 1;
    for(; b; b >>= 1, a = a * a % md){
        if(b & 1){
            ans = ans * a % md;
        }
    }
    return ans % md;
}

const int MAXN = 5e5 + 10;
const int MAXLG = 18;
const int MOD = 1e9 + 7;
const int MOD2 = 998244353;
const ll INF = 8e18;
int n, root, ans;
vector<int> adj[MAXN], leaf;
vector<pii> res;

void dfs(int v, int p = 0){
    if((int)adj[v].size() == 1){
        leaf.push_back(v);
    }
    for(auto u : adj[v]){
        if(u == p){
            continue;
        }
        dfs(u, v);
    }
}

int main()
{
    scanf("%d", &n);
    for(int i = 1; i < n; i++){
        int v, u;
        scanf("%d %d", &v, &u);
        adj[v].push_back(u);
        adj[u].push_back(v);
    }
    for(int i = 1; i <= n; i++){
        if((int)adj[i].size() > 1){
            root = i;
            break;
        }
    }
    dfs(root);
    int sz = (int)leaf.size();
    ans = sz / 2 + (sz & 1);
    int hv = sz / 2;
    for(int i = 0; i < hv; i++){
        res.push_back(mp(leaf[i], leaf[i + hv + (sz & 1)]));
    }
    if(sz & 1){
        res.push_back(mp(leaf[hv], root));
    }

    printf("%d\n", ans);
    for(int i = 0; i < ans; i++){
        printf("%d %d\n", res[i].F, res[i].S);
    }
}

Compilation message

net.cpp:3: warning: ignoring #pragma comment  [-Wunknown-pragmas]
    3 | #pragma comment(linker, "/stack:200000000")
      | 
net.cpp: In function 'int main()':
net.cpp:59:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   59 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
net.cpp:62:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   62 |         scanf("%d %d", &v, &u);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 11984 KB Output is correct
2 Correct 8 ms 12044 KB Output is correct
3 Correct 8 ms 12032 KB Output is correct
4 Correct 8 ms 11980 KB Output is correct
5 Correct 9 ms 11980 KB Output is correct
6 Correct 8 ms 11980 KB Output is correct
7 Correct 10 ms 11980 KB Output is correct
8 Correct 8 ms 11980 KB Output is correct
9 Correct 8 ms 11980 KB Output is correct
10 Correct 8 ms 11980 KB Output is correct
11 Correct 9 ms 11980 KB Output is correct
12 Correct 10 ms 11980 KB Output is correct
13 Correct 8 ms 11980 KB Output is correct
14 Correct 8 ms 11980 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 8 ms 12044 KB Output is correct
17 Correct 8 ms 11980 KB Output is correct
18 Correct 8 ms 11980 KB Output is correct
19 Correct 8 ms 11980 KB Output is correct
20 Correct 10 ms 11980 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 11984 KB Output is correct
2 Correct 8 ms 12044 KB Output is correct
3 Correct 8 ms 12032 KB Output is correct
4 Correct 8 ms 11980 KB Output is correct
5 Correct 9 ms 11980 KB Output is correct
6 Correct 8 ms 11980 KB Output is correct
7 Correct 10 ms 11980 KB Output is correct
8 Correct 8 ms 11980 KB Output is correct
9 Correct 8 ms 11980 KB Output is correct
10 Correct 8 ms 11980 KB Output is correct
11 Correct 9 ms 11980 KB Output is correct
12 Correct 10 ms 11980 KB Output is correct
13 Correct 8 ms 11980 KB Output is correct
14 Correct 8 ms 11980 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 8 ms 12044 KB Output is correct
17 Correct 8 ms 11980 KB Output is correct
18 Correct 8 ms 11980 KB Output is correct
19 Correct 8 ms 11980 KB Output is correct
20 Correct 10 ms 11980 KB Output is correct
21 Correct 10 ms 12040 KB Output is correct
22 Correct 11 ms 12108 KB Output is correct
23 Correct 10 ms 12124 KB Output is correct
24 Correct 9 ms 12136 KB Output is correct
25 Correct 9 ms 12108 KB Output is correct
26 Correct 9 ms 12108 KB Output is correct
27 Correct 9 ms 12108 KB Output is correct
28 Correct 10 ms 12056 KB Output is correct
29 Correct 9 ms 12048 KB Output is correct
30 Correct 8 ms 11980 KB Output is correct
31 Correct 10 ms 12120 KB Output is correct
32 Correct 8 ms 11980 KB Output is correct
33 Correct 8 ms 11980 KB Output is correct
34 Correct 8 ms 11980 KB Output is correct
35 Correct 8 ms 11980 KB Output is correct
36 Correct 10 ms 11952 KB Output is correct
37 Correct 8 ms 11980 KB Output is correct
38 Correct 9 ms 12108 KB Output is correct
39 Correct 10 ms 11980 KB Output is correct
40 Correct 8 ms 12044 KB Output is correct
41 Correct 8 ms 11980 KB Output is correct
42 Correct 8 ms 11980 KB Output is correct
43 Correct 9 ms 11980 KB Output is correct
44 Correct 8 ms 11980 KB Output is correct
45 Correct 8 ms 12108 KB Output is correct
46 Correct 9 ms 12056 KB Output is correct
47 Correct 9 ms 11980 KB Output is correct
48 Correct 8 ms 11980 KB Output is correct
49 Correct 9 ms 11992 KB Output is correct
50 Correct 8 ms 11980 KB Output is correct
51 Correct 8 ms 11980 KB Output is correct
52 Correct 9 ms 11980 KB Output is correct
53 Correct 8 ms 12088 KB Output is correct
54 Correct 8 ms 11992 KB Output is correct
55 Correct 9 ms 11968 KB Output is correct
56 Correct 8 ms 11984 KB Output is correct
57 Correct 10 ms 12096 KB Output is correct
58 Correct 9 ms 12108 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 11984 KB Output is correct
2 Correct 8 ms 12044 KB Output is correct
3 Correct 8 ms 12032 KB Output is correct
4 Correct 8 ms 11980 KB Output is correct
5 Correct 9 ms 11980 KB Output is correct
6 Correct 8 ms 11980 KB Output is correct
7 Correct 10 ms 11980 KB Output is correct
8 Correct 8 ms 11980 KB Output is correct
9 Correct 8 ms 11980 KB Output is correct
10 Correct 8 ms 11980 KB Output is correct
11 Correct 9 ms 11980 KB Output is correct
12 Correct 10 ms 11980 KB Output is correct
13 Correct 8 ms 11980 KB Output is correct
14 Correct 8 ms 11980 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 8 ms 12044 KB Output is correct
17 Correct 8 ms 11980 KB Output is correct
18 Correct 8 ms 11980 KB Output is correct
19 Correct 8 ms 11980 KB Output is correct
20 Correct 10 ms 11980 KB Output is correct
21 Correct 10 ms 12040 KB Output is correct
22 Correct 11 ms 12108 KB Output is correct
23 Correct 10 ms 12124 KB Output is correct
24 Correct 9 ms 12136 KB Output is correct
25 Correct 9 ms 12108 KB Output is correct
26 Correct 9 ms 12108 KB Output is correct
27 Correct 9 ms 12108 KB Output is correct
28 Correct 10 ms 12056 KB Output is correct
29 Correct 9 ms 12048 KB Output is correct
30 Correct 8 ms 11980 KB Output is correct
31 Correct 10 ms 12120 KB Output is correct
32 Correct 8 ms 11980 KB Output is correct
33 Correct 8 ms 11980 KB Output is correct
34 Correct 8 ms 11980 KB Output is correct
35 Correct 8 ms 11980 KB Output is correct
36 Correct 10 ms 11952 KB Output is correct
37 Correct 8 ms 11980 KB Output is correct
38 Correct 9 ms 12108 KB Output is correct
39 Correct 10 ms 11980 KB Output is correct
40 Correct 8 ms 12044 KB Output is correct
41 Correct 8 ms 11980 KB Output is correct
42 Correct 8 ms 11980 KB Output is correct
43 Correct 9 ms 11980 KB Output is correct
44 Correct 8 ms 11980 KB Output is correct
45 Correct 8 ms 12108 KB Output is correct
46 Correct 9 ms 12056 KB Output is correct
47 Correct 9 ms 11980 KB Output is correct
48 Correct 8 ms 11980 KB Output is correct
49 Correct 9 ms 11992 KB Output is correct
50 Correct 8 ms 11980 KB Output is correct
51 Correct 8 ms 11980 KB Output is correct
52 Correct 9 ms 11980 KB Output is correct
53 Correct 8 ms 12088 KB Output is correct
54 Correct 8 ms 11992 KB Output is correct
55 Correct 9 ms 11968 KB Output is correct
56 Correct 8 ms 11984 KB Output is correct
57 Correct 10 ms 12096 KB Output is correct
58 Correct 9 ms 12108 KB Output is correct
59 Correct 393 ms 31216 KB Output is correct
60 Correct 464 ms 33336 KB Output is correct
61 Correct 8 ms 11980 KB Output is correct
62 Correct 8 ms 11980 KB Output is correct
63 Correct 342 ms 29420 KB Output is correct
64 Correct 11 ms 12492 KB Output is correct
65 Correct 22 ms 13940 KB Output is correct
66 Correct 143 ms 28212 KB Output is correct
67 Correct 534 ms 44440 KB Output is correct
68 Correct 529 ms 45444 KB Output is correct
69 Correct 15 ms 12772 KB Output is correct
70 Correct 100 ms 19716 KB Output is correct
71 Correct 354 ms 36992 KB Output is correct
72 Correct 370 ms 36280 KB Output is correct
73 Correct 132 ms 17540 KB Output is correct
74 Correct 474 ms 31932 KB Output is correct
75 Correct 34 ms 14784 KB Output is correct
76 Correct 357 ms 36604 KB Output is correct
77 Correct 349 ms 37156 KB Output is correct
78 Correct 35 ms 15172 KB Output is correct
79 Correct 511 ms 42132 KB Output is correct
80 Correct 10 ms 12236 KB Output is correct
81 Correct 127 ms 19640 KB Output is correct
82 Correct 411 ms 34472 KB Output is correct
83 Correct 482 ms 31964 KB Output is correct
84 Correct 520 ms 31920 KB Output is correct
85 Correct 495 ms 31964 KB Output is correct
86 Correct 520 ms 33332 KB Output is correct
87 Correct 530 ms 33364 KB Output is correct