#include<bits/stdc++.h>
using namespace std;
using int64 = int64_t;
#define REP(i, n) for(int i = 0, _n = n; i < _n; ++i)
#define REPD(i, n) for(int i = n - 1; i >= 0; --i)
#define FOR(i, l, r) for(int i = l, _r = r; i <= _r; ++i)
#define FORD(i, r, l) for(int i = r, _l = l; i >= _l; --i)
#define left __left
#define right __right
#define prev __prev
#define next __next
#define div __div
#define pb push_back
#define pf push_front
#define sz(v) (int)v.size()
#define range(v) begin(v), end(v)
#define compact(v) v.erase(unique(range(v)), end(v))
#define debug(v) "[" #v " = " << (v) << "]"
template<typename T>
bool minimize(T& a, const T& b){
if(a > b){
a = b;
return true;
}
return false;
}
template<typename T>
bool maximize(T& a, const T& b){
if(a < b){
a = b;
return true;
}
return false;
}
template<int dimension, class T>
struct vec : public vector<vec<dimension - 1, T>> {
static_assert(dimension > 0, "Dimension must be positive !\n");
template<typename... Args>
vec(int n = 0, Args... args) : vector<vec<dimension - 1, T>>(n, vec<dimension - 1, T>(args...)) {}
};
template<class T>
struct vec<1, T> : public vector<T> {
vec(int n = 0, T val = T()) : vector<T>(n, val) {}
};
#define Zero_OP //turn off when submitting
#ifdef Zero_OP
void init(void);
void process(void);
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
#define task "antuvu"
if(fopen(task".inp", "r")){
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
int T = 1; //cin >> T;
while(T--) {
init();
process();
}
return 0;
}
const int MAX = 5e5 + 5;
int n;
vector<int> leaves, adj[MAX];
void init(){
cin >> n;
REP(i, n - 1){
int u, v;
cin >> u >> v;
--u, --v;
adj[u].pb(v);
adj[v].pb(u);
}
}
void dfs(int u, int pre){
if(sz(adj[u]) == 1) leaves.pb(u);
for(int v : adj[u]) if(v != pre){
dfs(v, u);
}
}
void process(){
dfs(0, -1);
int m = sz(leaves);
cout << (m + 1) / 2 << '\n';
REP(i, (m + 1) / 2){
cout << leaves[i] + 1 << ' ' << leaves[i + m / 2] + 1 << '\n';
}
}
#endif
Compilation message
net.cpp: In function 'int main()':
net.cpp:63:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
63 | freopen(task".inp", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
net.cpp:64:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
64 | freopen(task".out", "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
12120 KB |
Output is correct |
2 |
Correct |
3 ms |
12120 KB |
Output is correct |
3 |
Correct |
3 ms |
12124 KB |
Output is correct |
4 |
Correct |
3 ms |
12120 KB |
Output is correct |
5 |
Correct |
3 ms |
12124 KB |
Output is correct |
6 |
Correct |
3 ms |
12124 KB |
Output is correct |
7 |
Correct |
3 ms |
12120 KB |
Output is correct |
8 |
Correct |
3 ms |
12124 KB |
Output is correct |
9 |
Correct |
3 ms |
12124 KB |
Output is correct |
10 |
Correct |
3 ms |
12196 KB |
Output is correct |
11 |
Correct |
3 ms |
12124 KB |
Output is correct |
12 |
Correct |
3 ms |
12124 KB |
Output is correct |
13 |
Correct |
3 ms |
12612 KB |
Output is correct |
14 |
Correct |
6 ms |
12276 KB |
Output is correct |
15 |
Correct |
3 ms |
12124 KB |
Output is correct |
16 |
Correct |
3 ms |
12200 KB |
Output is correct |
17 |
Correct |
4 ms |
12120 KB |
Output is correct |
18 |
Correct |
3 ms |
12120 KB |
Output is correct |
19 |
Correct |
3 ms |
12124 KB |
Output is correct |
20 |
Correct |
3 ms |
12124 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
12120 KB |
Output is correct |
2 |
Correct |
3 ms |
12120 KB |
Output is correct |
3 |
Correct |
3 ms |
12124 KB |
Output is correct |
4 |
Correct |
3 ms |
12120 KB |
Output is correct |
5 |
Correct |
3 ms |
12124 KB |
Output is correct |
6 |
Correct |
3 ms |
12124 KB |
Output is correct |
7 |
Correct |
3 ms |
12120 KB |
Output is correct |
8 |
Correct |
3 ms |
12124 KB |
Output is correct |
9 |
Correct |
3 ms |
12124 KB |
Output is correct |
10 |
Correct |
3 ms |
12196 KB |
Output is correct |
11 |
Correct |
3 ms |
12124 KB |
Output is correct |
12 |
Correct |
3 ms |
12124 KB |
Output is correct |
13 |
Correct |
3 ms |
12612 KB |
Output is correct |
14 |
Correct |
6 ms |
12276 KB |
Output is correct |
15 |
Correct |
3 ms |
12124 KB |
Output is correct |
16 |
Correct |
3 ms |
12200 KB |
Output is correct |
17 |
Correct |
4 ms |
12120 KB |
Output is correct |
18 |
Correct |
3 ms |
12120 KB |
Output is correct |
19 |
Correct |
3 ms |
12124 KB |
Output is correct |
20 |
Correct |
3 ms |
12124 KB |
Output is correct |
21 |
Correct |
3 ms |
12124 KB |
Output is correct |
22 |
Correct |
4 ms |
12124 KB |
Output is correct |
23 |
Correct |
4 ms |
12124 KB |
Output is correct |
24 |
Correct |
4 ms |
12212 KB |
Output is correct |
25 |
Correct |
3 ms |
12124 KB |
Output is correct |
26 |
Correct |
3 ms |
12124 KB |
Output is correct |
27 |
Correct |
4 ms |
12124 KB |
Output is correct |
28 |
Correct |
3 ms |
12124 KB |
Output is correct |
29 |
Correct |
4 ms |
12124 KB |
Output is correct |
30 |
Correct |
3 ms |
12124 KB |
Output is correct |
31 |
Correct |
6 ms |
12124 KB |
Output is correct |
32 |
Correct |
3 ms |
12124 KB |
Output is correct |
33 |
Correct |
3 ms |
12120 KB |
Output is correct |
34 |
Correct |
3 ms |
12372 KB |
Output is correct |
35 |
Correct |
3 ms |
12120 KB |
Output is correct |
36 |
Correct |
4 ms |
12124 KB |
Output is correct |
37 |
Correct |
4 ms |
12200 KB |
Output is correct |
38 |
Correct |
3 ms |
12120 KB |
Output is correct |
39 |
Correct |
3 ms |
12120 KB |
Output is correct |
40 |
Correct |
3 ms |
12124 KB |
Output is correct |
41 |
Correct |
3 ms |
12196 KB |
Output is correct |
42 |
Correct |
3 ms |
12124 KB |
Output is correct |
43 |
Correct |
3 ms |
12124 KB |
Output is correct |
44 |
Correct |
3 ms |
12124 KB |
Output is correct |
45 |
Correct |
3 ms |
12124 KB |
Output is correct |
46 |
Correct |
3 ms |
12240 KB |
Output is correct |
47 |
Correct |
4 ms |
12124 KB |
Output is correct |
48 |
Correct |
3 ms |
12124 KB |
Output is correct |
49 |
Correct |
3 ms |
12124 KB |
Output is correct |
50 |
Correct |
3 ms |
12124 KB |
Output is correct |
51 |
Correct |
4 ms |
12120 KB |
Output is correct |
52 |
Correct |
3 ms |
12124 KB |
Output is correct |
53 |
Correct |
3 ms |
12124 KB |
Output is correct |
54 |
Correct |
3 ms |
12124 KB |
Output is correct |
55 |
Correct |
3 ms |
12124 KB |
Output is correct |
56 |
Correct |
3 ms |
12124 KB |
Output is correct |
57 |
Correct |
3 ms |
12124 KB |
Output is correct |
58 |
Correct |
4 ms |
12212 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
12120 KB |
Output is correct |
2 |
Correct |
3 ms |
12120 KB |
Output is correct |
3 |
Correct |
3 ms |
12124 KB |
Output is correct |
4 |
Correct |
3 ms |
12120 KB |
Output is correct |
5 |
Correct |
3 ms |
12124 KB |
Output is correct |
6 |
Correct |
3 ms |
12124 KB |
Output is correct |
7 |
Correct |
3 ms |
12120 KB |
Output is correct |
8 |
Correct |
3 ms |
12124 KB |
Output is correct |
9 |
Correct |
3 ms |
12124 KB |
Output is correct |
10 |
Correct |
3 ms |
12196 KB |
Output is correct |
11 |
Correct |
3 ms |
12124 KB |
Output is correct |
12 |
Correct |
3 ms |
12124 KB |
Output is correct |
13 |
Correct |
3 ms |
12612 KB |
Output is correct |
14 |
Correct |
6 ms |
12276 KB |
Output is correct |
15 |
Correct |
3 ms |
12124 KB |
Output is correct |
16 |
Correct |
3 ms |
12200 KB |
Output is correct |
17 |
Correct |
4 ms |
12120 KB |
Output is correct |
18 |
Correct |
3 ms |
12120 KB |
Output is correct |
19 |
Correct |
3 ms |
12124 KB |
Output is correct |
20 |
Correct |
3 ms |
12124 KB |
Output is correct |
21 |
Correct |
3 ms |
12124 KB |
Output is correct |
22 |
Correct |
4 ms |
12124 KB |
Output is correct |
23 |
Correct |
4 ms |
12124 KB |
Output is correct |
24 |
Correct |
4 ms |
12212 KB |
Output is correct |
25 |
Correct |
3 ms |
12124 KB |
Output is correct |
26 |
Correct |
3 ms |
12124 KB |
Output is correct |
27 |
Correct |
4 ms |
12124 KB |
Output is correct |
28 |
Correct |
3 ms |
12124 KB |
Output is correct |
29 |
Correct |
4 ms |
12124 KB |
Output is correct |
30 |
Correct |
3 ms |
12124 KB |
Output is correct |
31 |
Correct |
6 ms |
12124 KB |
Output is correct |
32 |
Correct |
3 ms |
12124 KB |
Output is correct |
33 |
Correct |
3 ms |
12120 KB |
Output is correct |
34 |
Correct |
3 ms |
12372 KB |
Output is correct |
35 |
Correct |
3 ms |
12120 KB |
Output is correct |
36 |
Correct |
4 ms |
12124 KB |
Output is correct |
37 |
Correct |
4 ms |
12200 KB |
Output is correct |
38 |
Correct |
3 ms |
12120 KB |
Output is correct |
39 |
Correct |
3 ms |
12120 KB |
Output is correct |
40 |
Correct |
3 ms |
12124 KB |
Output is correct |
41 |
Correct |
3 ms |
12196 KB |
Output is correct |
42 |
Correct |
3 ms |
12124 KB |
Output is correct |
43 |
Correct |
3 ms |
12124 KB |
Output is correct |
44 |
Correct |
3 ms |
12124 KB |
Output is correct |
45 |
Correct |
3 ms |
12124 KB |
Output is correct |
46 |
Correct |
3 ms |
12240 KB |
Output is correct |
47 |
Correct |
4 ms |
12124 KB |
Output is correct |
48 |
Correct |
3 ms |
12124 KB |
Output is correct |
49 |
Correct |
3 ms |
12124 KB |
Output is correct |
50 |
Correct |
3 ms |
12124 KB |
Output is correct |
51 |
Correct |
4 ms |
12120 KB |
Output is correct |
52 |
Correct |
3 ms |
12124 KB |
Output is correct |
53 |
Correct |
3 ms |
12124 KB |
Output is correct |
54 |
Correct |
3 ms |
12124 KB |
Output is correct |
55 |
Correct |
3 ms |
12124 KB |
Output is correct |
56 |
Correct |
3 ms |
12124 KB |
Output is correct |
57 |
Correct |
3 ms |
12124 KB |
Output is correct |
58 |
Correct |
4 ms |
12212 KB |
Output is correct |
59 |
Correct |
199 ms |
36124 KB |
Output is correct |
60 |
Correct |
263 ms |
38848 KB |
Output is correct |
61 |
Correct |
3 ms |
12120 KB |
Output is correct |
62 |
Correct |
3 ms |
12120 KB |
Output is correct |
63 |
Correct |
182 ms |
33644 KB |
Output is correct |
64 |
Correct |
5 ms |
12376 KB |
Output is correct |
65 |
Correct |
11 ms |
14004 KB |
Output is correct |
66 |
Correct |
65 ms |
27988 KB |
Output is correct |
67 |
Correct |
322 ms |
46928 KB |
Output is correct |
68 |
Correct |
338 ms |
47740 KB |
Output is correct |
69 |
Correct |
8 ms |
13132 KB |
Output is correct |
70 |
Correct |
49 ms |
21356 KB |
Output is correct |
71 |
Correct |
191 ms |
41980 KB |
Output is correct |
72 |
Correct |
211 ms |
40852 KB |
Output is correct |
73 |
Correct |
46 ms |
19152 KB |
Output is correct |
74 |
Correct |
288 ms |
37668 KB |
Output is correct |
75 |
Correct |
17 ms |
15404 KB |
Output is correct |
76 |
Correct |
203 ms |
41644 KB |
Output is correct |
77 |
Correct |
194 ms |
41692 KB |
Output is correct |
78 |
Correct |
19 ms |
15452 KB |
Output is correct |
79 |
Correct |
361 ms |
45292 KB |
Output is correct |
80 |
Correct |
4 ms |
12376 KB |
Output is correct |
81 |
Correct |
60 ms |
21448 KB |
Output is correct |
82 |
Correct |
224 ms |
39648 KB |
Output is correct |
83 |
Correct |
250 ms |
37828 KB |
Output is correct |
84 |
Correct |
253 ms |
37828 KB |
Output is correct |
85 |
Correct |
270 ms |
37632 KB |
Output is correct |
86 |
Correct |
246 ms |
38856 KB |
Output is correct |
87 |
Correct |
262 ms |
38832 KB |
Output is correct |