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Submission #313330

# Submission time Handle Problem Language Result Execution time Memory
313330 2020-10-15T18:14:08 Z vivaan_gupta Network (BOI15_net) C++14
100 / 100
 1386 ms 62704 KB 
#include <bits/stdc++.h>
using namespace std;
 
using ll = long long;
using ld = long double;
using db = double; 
using str = string; // yay python!
 
using pi = pair<int,int>;
using pl = pair<ll,ll>;
using pd = pair<db,db>;
 
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>; 
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>; 
using vpd = vector<pd>; 
// pairs
#define mp make_pair
#define f first
#define s second
 
// vectors
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend() 
#define sor(x) sort(all(x)) 
#define rsz resize
#define ins insert 
#define ft front() 
#define bk back()
#define pf push_front 
#define pb push_back
#define eb emplace_back 
#define lb lower_bound 
#define ub upper_bound 
 
// loops
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)
 

const ll N = 5e5+5;
vector<int> adj[N];
int dist[N];
vl le;
int cnt = 0;
void dfs(int u,int p,int h){
	dist[u] = h;
	if(sz(adj[u]) == 1) {
		cnt++;
		le.pb(u);
	}
	for(auto v:adj[u]){
		if(v!=p){
			dfs(v,u,h+1);
		}
	}
}
bool cmp(int i,int j){
	return dist[i] < dist[j];
}
int main() {	
	// you should actually read the stuff at the bottom
		int n;
	cin >> n;
	for(int i =2;i<=n;i++){
		int u,v;
		cin>>u>>v;
		adj[u].pb(v);
		adj[v].pb(u);
	}
	dfs(1,0,0);
	
	if(cnt%2==0){
		cnt ++ ;
		cnt /= 2;
		cout << cnt << endl;
		for(int i =0;i<cnt;i++){
			cout << le[i] << " " << le[i+(sz(le)/2)] << endl;
		}
		return 0;
	}
	cout << (cnt + 1) / 2 << endl;
	cnt ++;
	cnt /= 2;
	for(int i =0;i<cnt-1;i++){
		cout << le[i] << " " << le[i+(sz(le)/2)] << endl;
	}
	cout << le[0] << " " << le.back() << endl;
	return 0;
}
 
/* stuff you should look for
	* read the probem 3 more times in case of WA :)
	* int overflow, array bounds
	* special cases (n=1?)
	* do smth instead of nothing and stay organized
	* WRITE STUFF DOWN
	* DON'T GET STUCK ON ONE APPROACH
*/

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 12032 KB Output is correct
2 Correct 8 ms 12032 KB Output is correct
3 Correct 10 ms 12160 KB Output is correct
4 Correct 9 ms 12032 KB Output is correct
5 Correct 8 ms 12032 KB Output is correct
6 Correct 8 ms 12032 KB Output is correct
7 Correct 8 ms 12032 KB Output is correct
8 Correct 9 ms 12032 KB Output is correct
9 Correct 8 ms 12032 KB Output is correct
10 Correct 8 ms 12032 KB Output is correct
11 Correct 8 ms 12032 KB Output is correct
12 Correct 8 ms 12032 KB Output is correct
13 Correct 9 ms 12032 KB Output is correct
14 Correct 8 ms 12032 KB Output is correct
15 Correct 9 ms 12032 KB Output is correct
16 Correct 8 ms 12032 KB Output is correct
17 Correct 9 ms 12032 KB Output is correct
18 Correct 8 ms 12032 KB Output is correct
19 Correct 8 ms 12032 KB Output is correct
20 Correct 9 ms 12032 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 12032 KB Output is correct
2 Correct 8 ms 12032 KB Output is correct
3 Correct 10 ms 12160 KB Output is correct
4 Correct 9 ms 12032 KB Output is correct
5 Correct 8 ms 12032 KB Output is correct
6 Correct 8 ms 12032 KB Output is correct
7 Correct 8 ms 12032 KB Output is correct
8 Correct 9 ms 12032 KB Output is correct
9 Correct 8 ms 12032 KB Output is correct
10 Correct 8 ms 12032 KB Output is correct
11 Correct 8 ms 12032 KB Output is correct
12 Correct 8 ms 12032 KB Output is correct
13 Correct 9 ms 12032 KB Output is correct
14 Correct 8 ms 12032 KB Output is correct
15 Correct 9 ms 12032 KB Output is correct
16 Correct 8 ms 12032 KB Output is correct
17 Correct 9 ms 12032 KB Output is correct
18 Correct 8 ms 12032 KB Output is correct
19 Correct 8 ms 12032 KB Output is correct
20 Correct 9 ms 12032 KB Output is correct
21 Correct 9 ms 12032 KB Output is correct
22 Correct 13 ms 12160 KB Output is correct
23 Correct 13 ms 12160 KB Output is correct
24 Correct 13 ms 12160 KB Output is correct
25 Correct 12 ms 12160 KB Output is correct
26 Correct 11 ms 12160 KB Output is correct
27 Correct 12 ms 12160 KB Output is correct
28 Correct 12 ms 12160 KB Output is correct
29 Correct 11 ms 12160 KB Output is correct
30 Correct 9 ms 12032 KB Output is correct
31 Correct 13 ms 12160 KB Output is correct
32 Correct 9 ms 12032 KB Output is correct
33 Correct 9 ms 12032 KB Output is correct
34 Correct 8 ms 12032 KB Output is correct
35 Correct 9 ms 12032 KB Output is correct
36 Correct 8 ms 12032 KB Output is correct
37 Correct 9 ms 12160 KB Output is correct
38 Correct 9 ms 12160 KB Output is correct
39 Correct 9 ms 12160 KB Output is correct
40 Correct 9 ms 12032 KB Output is correct
41 Correct 9 ms 12032 KB Output is correct
42 Correct 9 ms 12032 KB Output is correct
43 Correct 11 ms 12160 KB Output is correct
44 Correct 8 ms 12032 KB Output is correct
45 Correct 9 ms 12032 KB Output is correct
46 Correct 10 ms 12160 KB Output is correct
47 Correct 9 ms 12032 KB Output is correct
48 Correct 9 ms 12032 KB Output is correct
49 Correct 12 ms 12160 KB Output is correct
50 Correct 9 ms 12032 KB Output is correct
51 Correct 9 ms 12032 KB Output is correct
52 Correct 9 ms 12032 KB Output is correct
53 Correct 10 ms 12160 KB Output is correct
54 Correct 8 ms 12032 KB Output is correct
55 Correct 9 ms 12032 KB Output is correct
56 Correct 9 ms 12032 KB Output is correct
57 Correct 9 ms 12032 KB Output is correct
58 Correct 13 ms 12160 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 12032 KB Output is correct
2 Correct 8 ms 12032 KB Output is correct
3 Correct 10 ms 12160 KB Output is correct
4 Correct 9 ms 12032 KB Output is correct
5 Correct 8 ms 12032 KB Output is correct
6 Correct 8 ms 12032 KB Output is correct
7 Correct 8 ms 12032 KB Output is correct
8 Correct 9 ms 12032 KB Output is correct
9 Correct 8 ms 12032 KB Output is correct
10 Correct 8 ms 12032 KB Output is correct
11 Correct 8 ms 12032 KB Output is correct
12 Correct 8 ms 12032 KB Output is correct
13 Correct 9 ms 12032 KB Output is correct
14 Correct 8 ms 12032 KB Output is correct
15 Correct 9 ms 12032 KB Output is correct
16 Correct 8 ms 12032 KB Output is correct
17 Correct 9 ms 12032 KB Output is correct
18 Correct 8 ms 12032 KB Output is correct
19 Correct 8 ms 12032 KB Output is correct
20 Correct 9 ms 12032 KB Output is correct
21 Correct 9 ms 12032 KB Output is correct
22 Correct 13 ms 12160 KB Output is correct
23 Correct 13 ms 12160 KB Output is correct
24 Correct 13 ms 12160 KB Output is correct
25 Correct 12 ms 12160 KB Output is correct
26 Correct 11 ms 12160 KB Output is correct
27 Correct 12 ms 12160 KB Output is correct
28 Correct 12 ms 12160 KB Output is correct
29 Correct 11 ms 12160 KB Output is correct
30 Correct 9 ms 12032 KB Output is correct
31 Correct 13 ms 12160 KB Output is correct
32 Correct 9 ms 12032 KB Output is correct
33 Correct 9 ms 12032 KB Output is correct
34 Correct 8 ms 12032 KB Output is correct
35 Correct 9 ms 12032 KB Output is correct
36 Correct 8 ms 12032 KB Output is correct
37 Correct 9 ms 12160 KB Output is correct
38 Correct 9 ms 12160 KB Output is correct
39 Correct 9 ms 12160 KB Output is correct
40 Correct 9 ms 12032 KB Output is correct
41 Correct 9 ms 12032 KB Output is correct
42 Correct 9 ms 12032 KB Output is correct
43 Correct 11 ms 12160 KB Output is correct
44 Correct 8 ms 12032 KB Output is correct
45 Correct 9 ms 12032 KB Output is correct
46 Correct 10 ms 12160 KB Output is correct
47 Correct 9 ms 12032 KB Output is correct
48 Correct 9 ms 12032 KB Output is correct
49 Correct 12 ms 12160 KB Output is correct
50 Correct 9 ms 12032 KB Output is correct
51 Correct 9 ms 12032 KB Output is correct
52 Correct 9 ms 12032 KB Output is correct
53 Correct 10 ms 12160 KB Output is correct
54 Correct 8 ms 12032 KB Output is correct
55 Correct 9 ms 12032 KB Output is correct
56 Correct 9 ms 12032 KB Output is correct
57 Correct 9 ms 12032 KB Output is correct
58 Correct 13 ms 12160 KB Output is correct
59 Correct 1197 ms 39220 KB Output is correct
60 Correct 1365 ms 42064 KB Output is correct
61 Correct 9 ms 12032 KB Output is correct
62 Correct 9 ms 12032 KB Output is correct
63 Correct 1082 ms 36456 KB Output is correct
64 Correct 15 ms 12672 KB Output is correct
65 Correct 42 ms 14840 KB Output is correct
66 Correct 353 ms 36568 KB Output is correct
67 Correct 1042 ms 61588 KB Output is correct
68 Correct 1078 ms 62704 KB Output is correct
69 Correct 42 ms 13184 KB Output is correct
70 Correct 419 ms 22580 KB Output is correct
71 Correct 1386 ms 45972 KB Output is correct
72 Correct 1329 ms 44508 KB Output is correct
73 Correct 319 ms 20080 KB Output is correct
74 Correct 1271 ms 40904 KB Output is correct
75 Correct 143 ms 15860 KB Output is correct
76 Correct 1378 ms 45512 KB Output is correct
77 Correct 1367 ms 45652 KB Output is correct
78 Correct 102 ms 16504 KB Output is correct
79 Correct 1037 ms 58112 KB Output is correct
80 Correct 17 ms 12408 KB Output is correct
81 Correct 429 ms 22508 KB Output is correct
82 Correct 1323 ms 43088 KB Output is correct
83 Correct 1271 ms 40988 KB Output is correct
84 Correct 1272 ms 40828 KB Output is correct
85 Correct 1271 ms 40808 KB Output is correct
86 Correct 1346 ms 42332 KB Output is correct
87 Correct 1359 ms 42332 KB Output is correct