답안 #484417

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
484417	2021-11-03T09:26:40 Z	MilosMilutinovic	Network (BOI15_net)	C++14	100 / 100	398 ms	57612 KB

#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
mt19937 mrand(random_device{}());
const ll mod=1000000007;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=501000;
int n;
VI g[N],l;
void dfs(int x,int f) {
	bool lf=true;
	for (auto u:g[x]) {
		if (u!=f) {
			dfs(u,x);
			lf=false;
		}
	}
	if (lf) l.pb(x);
}
int main() {
	scanf("%d",&n);
	rep(i,1,n) {
		int x,y;
		scanf("%d%d",&x,&y);
		g[x].pb(y);
		g[y].pb(x);
	}
	int rt=-1;
	rep(i,1,n+1) if (SZ(g[i])>1) rt=i;
	assert(rt!=-1);
	dfs(rt,0);
	vector<PII> ans;
	for (int i=0;i<SZ(l)/2;i++) {
		ans.pb(mp(l[i],l[SZ(l)/2+i]));
	}
	if (SZ(l)&1) ans.pb(mp(l[0],l.back()));
	printf("%d\n",SZ(ans));
	rep(i,0,SZ(ans)) printf("%d %d\n",ans[i].fi,ans[i].se);
//	if (SZ(l)%2==1&&SZ(l)>1) printf("%d %d\n",l[SZ(l)-2],l[SZ(l)-1]);
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:36:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
net.cpp:39:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |   scanf("%d%d",&x,&y);
      |   ~~~~~^~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

#	결과	실행 시간	메모리	Grader output
1	Correct	6 ms	11980 KB	Output is correct
2	Correct	5 ms	12040 KB	Output is correct
3	Correct	5 ms	11980 KB	Output is correct
4	Correct	6 ms	12064 KB	Output is correct
5	Correct	6 ms	11980 KB	Output is correct
6	Correct	6 ms	11980 KB	Output is correct
7	Correct	7 ms	12064 KB	Output is correct
8	Correct	6 ms	11980 KB	Output is correct
9	Correct	6 ms	11980 KB	Output is correct
10	Correct	6 ms	11980 KB	Output is correct
11	Correct	5 ms	12012 KB	Output is correct
12	Correct	5 ms	11980 KB	Output is correct
13	Correct	5 ms	11980 KB	Output is correct
14	Correct	5 ms	11948 KB	Output is correct
15	Correct	5 ms	11980 KB	Output is correct
16	Correct	6 ms	11980 KB	Output is correct
17	Correct	6 ms	12004 KB	Output is correct
18	Correct	6 ms	12064 KB	Output is correct
19	Correct	6 ms	12028 KB	Output is correct
20	Correct	6 ms	12060 KB	Output is correct

Subtask #2
45.0 / 45.0

#	결과	실행 시간	메모리	Grader output
1	Correct	6 ms	11980 KB	Output is correct
2	Correct	5 ms	12040 KB	Output is correct
3	Correct	5 ms	11980 KB	Output is correct
4	Correct	6 ms	12064 KB	Output is correct
5	Correct	6 ms	11980 KB	Output is correct
6	Correct	6 ms	11980 KB	Output is correct
7	Correct	7 ms	12064 KB	Output is correct
8	Correct	6 ms	11980 KB	Output is correct
9	Correct	6 ms	11980 KB	Output is correct
10	Correct	6 ms	11980 KB	Output is correct
11	Correct	5 ms	12012 KB	Output is correct
12	Correct	5 ms	11980 KB	Output is correct
13	Correct	5 ms	11980 KB	Output is correct
14	Correct	5 ms	11948 KB	Output is correct
15	Correct	5 ms	11980 KB	Output is correct
16	Correct	6 ms	11980 KB	Output is correct
17	Correct	6 ms	12004 KB	Output is correct
18	Correct	6 ms	12064 KB	Output is correct
19	Correct	6 ms	12028 KB	Output is correct
20	Correct	6 ms	12060 KB	Output is correct
21	Correct	6 ms	11980 KB	Output is correct
22	Correct	6 ms	12108 KB	Output is correct
23	Correct	6 ms	12108 KB	Output is correct
24	Correct	6 ms	12108 KB	Output is correct
25	Correct	6 ms	12108 KB	Output is correct
26	Correct	6 ms	12108 KB	Output is correct
27	Correct	7 ms	12108 KB	Output is correct
28	Correct	6 ms	12108 KB	Output is correct
29	Correct	6 ms	12108 KB	Output is correct
30	Correct	6 ms	12032 KB	Output is correct
31	Correct	6 ms	12108 KB	Output is correct
32	Correct	6 ms	11980 KB	Output is correct
33	Correct	6 ms	12000 KB	Output is correct
34	Correct	6 ms	11980 KB	Output is correct
35	Correct	6 ms	11980 KB	Output is correct
36	Correct	6 ms	11980 KB	Output is correct
37	Correct	6 ms	11980 KB	Output is correct
38	Correct	6 ms	12108 KB	Output is correct
39	Correct	5 ms	11980 KB	Output is correct
40	Correct	7 ms	11980 KB	Output is correct
41	Correct	6 ms	11952 KB	Output is correct
42	Correct	6 ms	11980 KB	Output is correct
43	Correct	6 ms	12108 KB	Output is correct
44	Correct	6 ms	11980 KB	Output is correct
45	Correct	6 ms	11956 KB	Output is correct
46	Correct	6 ms	11980 KB	Output is correct
47	Correct	6 ms	11980 KB	Output is correct
48	Correct	6 ms	11980 KB	Output is correct
49	Correct	6 ms	12108 KB	Output is correct
50	Correct	5 ms	11980 KB	Output is correct
51	Correct	5 ms	11980 KB	Output is correct
52	Correct	6 ms	11980 KB	Output is correct
53	Correct	6 ms	12108 KB	Output is correct
54	Correct	6 ms	11980 KB	Output is correct
55	Correct	6 ms	11980 KB	Output is correct
56	Correct	6 ms	12024 KB	Output is correct
57	Correct	6 ms	11980 KB	Output is correct
58	Correct	6 ms	12108 KB	Output is correct

Subtask #3
37.0 / 37.0

#	결과	실행 시간	메모리	Grader output
1	Correct	6 ms	11980 KB	Output is correct
2	Correct	5 ms	12040 KB	Output is correct
3	Correct	5 ms	11980 KB	Output is correct
4	Correct	6 ms	12064 KB	Output is correct
5	Correct	6 ms	11980 KB	Output is correct
6	Correct	6 ms	11980 KB	Output is correct
7	Correct	7 ms	12064 KB	Output is correct
8	Correct	6 ms	11980 KB	Output is correct
9	Correct	6 ms	11980 KB	Output is correct
10	Correct	6 ms	11980 KB	Output is correct
11	Correct	5 ms	12012 KB	Output is correct
12	Correct	5 ms	11980 KB	Output is correct
13	Correct	5 ms	11980 KB	Output is correct
14	Correct	5 ms	11948 KB	Output is correct
15	Correct	5 ms	11980 KB	Output is correct
16	Correct	6 ms	11980 KB	Output is correct
17	Correct	6 ms	12004 KB	Output is correct
18	Correct	6 ms	12064 KB	Output is correct
19	Correct	6 ms	12028 KB	Output is correct
20	Correct	6 ms	12060 KB	Output is correct
21	Correct	6 ms	11980 KB	Output is correct
22	Correct	6 ms	12108 KB	Output is correct
23	Correct	6 ms	12108 KB	Output is correct
24	Correct	6 ms	12108 KB	Output is correct
25	Correct	6 ms	12108 KB	Output is correct
26	Correct	6 ms	12108 KB	Output is correct
27	Correct	7 ms	12108 KB	Output is correct
28	Correct	6 ms	12108 KB	Output is correct
29	Correct	6 ms	12108 KB	Output is correct
30	Correct	6 ms	12032 KB	Output is correct
31	Correct	6 ms	12108 KB	Output is correct
32	Correct	6 ms	11980 KB	Output is correct
33	Correct	6 ms	12000 KB	Output is correct
34	Correct	6 ms	11980 KB	Output is correct
35	Correct	6 ms	11980 KB	Output is correct
36	Correct	6 ms	11980 KB	Output is correct
37	Correct	6 ms	11980 KB	Output is correct
38	Correct	6 ms	12108 KB	Output is correct
39	Correct	5 ms	11980 KB	Output is correct
40	Correct	7 ms	11980 KB	Output is correct
41	Correct	6 ms	11952 KB	Output is correct
42	Correct	6 ms	11980 KB	Output is correct
43	Correct	6 ms	12108 KB	Output is correct
44	Correct	6 ms	11980 KB	Output is correct
45	Correct	6 ms	11956 KB	Output is correct
46	Correct	6 ms	11980 KB	Output is correct
47	Correct	6 ms	11980 KB	Output is correct
48	Correct	6 ms	11980 KB	Output is correct
49	Correct	6 ms	12108 KB	Output is correct
50	Correct	5 ms	11980 KB	Output is correct
51	Correct	5 ms	11980 KB	Output is correct
52	Correct	6 ms	11980 KB	Output is correct
53	Correct	6 ms	12108 KB	Output is correct
54	Correct	6 ms	11980 KB	Output is correct
55	Correct	6 ms	11980 KB	Output is correct
56	Correct	6 ms	12024 KB	Output is correct
57	Correct	6 ms	11980 KB	Output is correct
58	Correct	6 ms	12108 KB	Output is correct
59	Correct	288 ms	37068 KB	Output is correct
60	Correct	363 ms	40048 KB	Output is correct
61	Correct	6 ms	11980 KB	Output is correct
62	Correct	6 ms	12000 KB	Output is correct
63	Correct	252 ms	34740 KB	Output is correct
64	Correct	9 ms	12364 KB	Output is correct
65	Correct	17 ms	13864 KB	Output is correct
66	Correct	105 ms	25052 KB	Output is correct
67	Correct	390 ms	57612 KB	Output is correct
68	Correct	390 ms	50756 KB	Output is correct
69	Correct	12 ms	13004 KB	Output is correct
70	Correct	76 ms	21824 KB	Output is correct
71	Correct	266 ms	43732 KB	Output is correct
72	Correct	284 ms	42424 KB	Output is correct
73	Correct	69 ms	19244 KB	Output is correct
74	Correct	374 ms	38716 KB	Output is correct
75	Correct	27 ms	15432 KB	Output is correct
76	Correct	268 ms	43368 KB	Output is correct
77	Correct	277 ms	43520 KB	Output is correct
78	Correct	28 ms	15400 KB	Output is correct
79	Correct	398 ms	45000 KB	Output is correct
80	Correct	9 ms	12236 KB	Output is correct
81	Correct	90 ms	21876 KB	Output is correct
82	Correct	308 ms	40976 KB	Output is correct
83	Correct	352 ms	38652 KB	Output is correct
84	Correct	347 ms	38596 KB	Output is correct
85	Correct	354 ms	38628 KB	Output is correct
86	Correct	365 ms	39996 KB	Output is correct
87	Correct	365 ms	40112 KB	Output is correct

답안 #484417

Compilation message

Subtask #1 18.0 / 18.0

Subtask #2 45.0 / 45.0

Subtask #3 37.0 / 37.0

Subtask #1
18.0 / 18.0

Subtask #2
45.0 / 45.0

Subtask #3
37.0 / 37.0