/** MIT License Copyright (c) 2018 Vasilyev Daniil **/
#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast")
template<typename T> using v = vector<T>;
#define int long long
typedef string str;
typedef vector<int> vint;
#define rep(a, l, r) for(int a = (l); a < (r); a++)
#define pb push_back
#define sz(a) ((int) a.size())
const long long inf = 4611686018427387903; //2^62 - 1
#if 0 //FileIO
const string fileName = "";
ifstream fin ((fileName == "" ? "input.txt" : fileName + ".in" ));
ofstream fout((fileName == "" ? "output.txt" : fileName + ".out"));
#define get fin>>
#define put fout<<
#else
#define get cin>>
#define put cout<<
#endif
#define eol put endl
void read() {} template<typename Arg,typename... Args> void read (Arg& arg,Args&... args){get (arg) ;read(args...) ;}
void print(){} template<typename Arg,typename... Args> void print(Arg arg,Args... args){put (arg)<<" ";print(args...);}
void debug(){eol;} template<typename Arg,typename... Args> void debug(Arg arg,Args... args){put (arg)<<" ";debug(args...);}
int getInt(){int a; get a; return a;}
//code goes here
const int N = 600001;
vint g[N];
v<pair<int, int>> ans;
vint dfs(int cur, int p = -1) {
if (sz(g[cur]) == 1)
return vint({cur});
else {
vint pos;
for (int i : g[cur]) {
if (i == p)
continue;
vint z = dfs(i, cur);
if (sz(z) == 2 && sz(pos) == 0)
for (int j : z)
pos.pb(j);
else if (sz(z) == 2 && sz(pos) == 1)
for (int j : z)
if (pos.empty())
pos.pb(j);
else {
ans.pb({pos.back(), j});
pos.pop_back();
}
else
for (int j : z)
if (sz(pos) < 2)
pos.pb(j);
else {
ans.pb({pos.back(), j});
pos.pop_back();
}
}
if (p == -1) {
if (sz(pos) == 2)
ans.pb({pos[0], pos[1]});
else
rep(i, 1, N)
if (pos[0] != i && g[pos[0]][0] != i) {
ans.pb({pos[0], i});
break;
}
}
return pos;
}
}
void run() {
int n;
get n;
n++;
rep(i, 2, n) {
int v, u;
read(v, u);
g[v].pb(u);
g[u].pb(v);
}
rep(i, 1, n)
if (sz(g[i]) != 1) {
dfs(i);
break;
}
put sz(ans);
eol;
for (auto i : ans)
debug(i.first, i.second);
}
int32_t main() {srand(time(0)); ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); put fixed; put setprecision(15); run(); return 0;}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
17 ms |
14456 KB |
Output is correct |
2 |
Correct |
17 ms |
14456 KB |
Output is correct |
3 |
Correct |
16 ms |
14500 KB |
Output is correct |
4 |
Correct |
16 ms |
14504 KB |
Output is correct |
5 |
Correct |
17 ms |
14508 KB |
Output is correct |
6 |
Correct |
17 ms |
14512 KB |
Output is correct |
7 |
Correct |
19 ms |
14624 KB |
Output is correct |
8 |
Correct |
17 ms |
14624 KB |
Output is correct |
9 |
Correct |
16 ms |
14628 KB |
Output is correct |
10 |
Correct |
14 ms |
14628 KB |
Output is correct |
11 |
Correct |
15 ms |
14628 KB |
Output is correct |
12 |
Correct |
16 ms |
14628 KB |
Output is correct |
13 |
Correct |
15 ms |
14640 KB |
Output is correct |
14 |
Correct |
17 ms |
14752 KB |
Output is correct |
15 |
Correct |
17 ms |
14884 KB |
Output is correct |
16 |
Correct |
17 ms |
14884 KB |
Output is correct |
17 |
Correct |
15 ms |
14884 KB |
Output is correct |
18 |
Correct |
17 ms |
14884 KB |
Output is correct |
19 |
Correct |
18 ms |
14884 KB |
Output is correct |
20 |
Correct |
19 ms |
14884 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
17 ms |
14456 KB |
Output is correct |
2 |
Correct |
17 ms |
14456 KB |
Output is correct |
3 |
Correct |
16 ms |
14500 KB |
Output is correct |
4 |
Correct |
16 ms |
14504 KB |
Output is correct |
5 |
Correct |
17 ms |
14508 KB |
Output is correct |
6 |
Correct |
17 ms |
14512 KB |
Output is correct |
7 |
Correct |
19 ms |
14624 KB |
Output is correct |
8 |
Correct |
17 ms |
14624 KB |
Output is correct |
9 |
Correct |
16 ms |
14628 KB |
Output is correct |
10 |
Correct |
14 ms |
14628 KB |
Output is correct |
11 |
Correct |
15 ms |
14628 KB |
Output is correct |
12 |
Correct |
16 ms |
14628 KB |
Output is correct |
13 |
Correct |
15 ms |
14640 KB |
Output is correct |
14 |
Correct |
17 ms |
14752 KB |
Output is correct |
15 |
Correct |
17 ms |
14884 KB |
Output is correct |
16 |
Correct |
17 ms |
14884 KB |
Output is correct |
17 |
Correct |
15 ms |
14884 KB |
Output is correct |
18 |
Correct |
17 ms |
14884 KB |
Output is correct |
19 |
Correct |
18 ms |
14884 KB |
Output is correct |
20 |
Correct |
19 ms |
14884 KB |
Output is correct |
21 |
Correct |
14 ms |
14884 KB |
Output is correct |
22 |
Correct |
20 ms |
14884 KB |
Output is correct |
23 |
Correct |
19 ms |
14900 KB |
Output is correct |
24 |
Correct |
21 ms |
14936 KB |
Output is correct |
25 |
Correct |
22 ms |
14972 KB |
Output is correct |
26 |
Correct |
20 ms |
14972 KB |
Output is correct |
27 |
Correct |
17 ms |
15016 KB |
Output is correct |
28 |
Correct |
20 ms |
15036 KB |
Output is correct |
29 |
Correct |
18 ms |
15036 KB |
Output is correct |
30 |
Correct |
17 ms |
15036 KB |
Output is correct |
31 |
Correct |
22 ms |
15076 KB |
Output is correct |
32 |
Correct |
18 ms |
15076 KB |
Output is correct |
33 |
Correct |
17 ms |
15076 KB |
Output is correct |
34 |
Correct |
15 ms |
15076 KB |
Output is correct |
35 |
Correct |
18 ms |
15076 KB |
Output is correct |
36 |
Correct |
16 ms |
15076 KB |
Output is correct |
37 |
Correct |
18 ms |
15076 KB |
Output is correct |
38 |
Correct |
15 ms |
15100 KB |
Output is correct |
39 |
Correct |
16 ms |
15100 KB |
Output is correct |
40 |
Correct |
16 ms |
15136 KB |
Output is correct |
41 |
Correct |
14 ms |
15136 KB |
Output is correct |
42 |
Correct |
14 ms |
15136 KB |
Output is correct |
43 |
Correct |
19 ms |
15136 KB |
Output is correct |
44 |
Correct |
17 ms |
15136 KB |
Output is correct |
45 |
Correct |
15 ms |
15136 KB |
Output is correct |
46 |
Correct |
15 ms |
15136 KB |
Output is correct |
47 |
Correct |
14 ms |
15136 KB |
Output is correct |
48 |
Correct |
16 ms |
15136 KB |
Output is correct |
49 |
Correct |
18 ms |
15164 KB |
Output is correct |
50 |
Correct |
19 ms |
15164 KB |
Output is correct |
51 |
Correct |
19 ms |
15164 KB |
Output is correct |
52 |
Correct |
19 ms |
15164 KB |
Output is correct |
53 |
Correct |
21 ms |
15164 KB |
Output is correct |
54 |
Correct |
18 ms |
15164 KB |
Output is correct |
55 |
Correct |
18 ms |
15164 KB |
Output is correct |
56 |
Correct |
17 ms |
15164 KB |
Output is correct |
57 |
Correct |
15 ms |
15164 KB |
Output is correct |
58 |
Correct |
20 ms |
15200 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
17 ms |
14456 KB |
Output is correct |
2 |
Correct |
17 ms |
14456 KB |
Output is correct |
3 |
Correct |
16 ms |
14500 KB |
Output is correct |
4 |
Correct |
16 ms |
14504 KB |
Output is correct |
5 |
Correct |
17 ms |
14508 KB |
Output is correct |
6 |
Correct |
17 ms |
14512 KB |
Output is correct |
7 |
Correct |
19 ms |
14624 KB |
Output is correct |
8 |
Correct |
17 ms |
14624 KB |
Output is correct |
9 |
Correct |
16 ms |
14628 KB |
Output is correct |
10 |
Correct |
14 ms |
14628 KB |
Output is correct |
11 |
Correct |
15 ms |
14628 KB |
Output is correct |
12 |
Correct |
16 ms |
14628 KB |
Output is correct |
13 |
Correct |
15 ms |
14640 KB |
Output is correct |
14 |
Correct |
17 ms |
14752 KB |
Output is correct |
15 |
Correct |
17 ms |
14884 KB |
Output is correct |
16 |
Correct |
17 ms |
14884 KB |
Output is correct |
17 |
Correct |
15 ms |
14884 KB |
Output is correct |
18 |
Correct |
17 ms |
14884 KB |
Output is correct |
19 |
Correct |
18 ms |
14884 KB |
Output is correct |
20 |
Correct |
19 ms |
14884 KB |
Output is correct |
21 |
Correct |
14 ms |
14884 KB |
Output is correct |
22 |
Correct |
20 ms |
14884 KB |
Output is correct |
23 |
Correct |
19 ms |
14900 KB |
Output is correct |
24 |
Correct |
21 ms |
14936 KB |
Output is correct |
25 |
Correct |
22 ms |
14972 KB |
Output is correct |
26 |
Correct |
20 ms |
14972 KB |
Output is correct |
27 |
Correct |
17 ms |
15016 KB |
Output is correct |
28 |
Correct |
20 ms |
15036 KB |
Output is correct |
29 |
Correct |
18 ms |
15036 KB |
Output is correct |
30 |
Correct |
17 ms |
15036 KB |
Output is correct |
31 |
Correct |
22 ms |
15076 KB |
Output is correct |
32 |
Correct |
18 ms |
15076 KB |
Output is correct |
33 |
Correct |
17 ms |
15076 KB |
Output is correct |
34 |
Correct |
15 ms |
15076 KB |
Output is correct |
35 |
Correct |
18 ms |
15076 KB |
Output is correct |
36 |
Correct |
16 ms |
15076 KB |
Output is correct |
37 |
Correct |
18 ms |
15076 KB |
Output is correct |
38 |
Correct |
15 ms |
15100 KB |
Output is correct |
39 |
Correct |
16 ms |
15100 KB |
Output is correct |
40 |
Correct |
16 ms |
15136 KB |
Output is correct |
41 |
Correct |
14 ms |
15136 KB |
Output is correct |
42 |
Correct |
14 ms |
15136 KB |
Output is correct |
43 |
Correct |
19 ms |
15136 KB |
Output is correct |
44 |
Correct |
17 ms |
15136 KB |
Output is correct |
45 |
Correct |
15 ms |
15136 KB |
Output is correct |
46 |
Correct |
15 ms |
15136 KB |
Output is correct |
47 |
Correct |
14 ms |
15136 KB |
Output is correct |
48 |
Correct |
16 ms |
15136 KB |
Output is correct |
49 |
Correct |
18 ms |
15164 KB |
Output is correct |
50 |
Correct |
19 ms |
15164 KB |
Output is correct |
51 |
Correct |
19 ms |
15164 KB |
Output is correct |
52 |
Correct |
19 ms |
15164 KB |
Output is correct |
53 |
Correct |
21 ms |
15164 KB |
Output is correct |
54 |
Correct |
18 ms |
15164 KB |
Output is correct |
55 |
Correct |
18 ms |
15164 KB |
Output is correct |
56 |
Correct |
17 ms |
15164 KB |
Output is correct |
57 |
Correct |
15 ms |
15164 KB |
Output is correct |
58 |
Correct |
20 ms |
15200 KB |
Output is correct |
59 |
Correct |
778 ms |
40160 KB |
Output is correct |
60 |
Correct |
889 ms |
42424 KB |
Output is correct |
61 |
Correct |
14 ms |
42424 KB |
Output is correct |
62 |
Correct |
15 ms |
42424 KB |
Output is correct |
63 |
Correct |
737 ms |
42424 KB |
Output is correct |
64 |
Correct |
18 ms |
42424 KB |
Output is correct |
65 |
Correct |
39 ms |
42424 KB |
Output is correct |
66 |
Correct |
256 ms |
52380 KB |
Output is correct |
67 |
Correct |
766 ms |
79388 KB |
Output is correct |
68 |
Correct |
848 ms |
81912 KB |
Output is correct |
69 |
Correct |
35 ms |
81912 KB |
Output is correct |
70 |
Correct |
338 ms |
81912 KB |
Output is correct |
71 |
Correct |
923 ms |
81912 KB |
Output is correct |
72 |
Correct |
786 ms |
81912 KB |
Output is correct |
73 |
Correct |
212 ms |
81912 KB |
Output is correct |
74 |
Correct |
978 ms |
81912 KB |
Output is correct |
75 |
Correct |
107 ms |
81912 KB |
Output is correct |
76 |
Correct |
965 ms |
81912 KB |
Output is correct |
77 |
Correct |
851 ms |
81912 KB |
Output is correct |
78 |
Incorrect |
76 ms |
81912 KB |
Breaking single line is causing network to disconnect. |
79 |
Halted |
0 ms |
0 KB |
- |