#include <bits/stdc++.h>
using std::vector;
using std::array;
using std::pair;
using std::tuple;
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
int N, M;
std::cin >> N >> M;
if (M != N - 1) {
std::cout << "NO\n";
return 0;
}
if (N == 1) {
std::cout << "YES\n1\n1\n";
return 0;
}
vector<vector<int>> graph(N);
for (int i = 0; i < M; ++i) {
int a, b;
std::cin >> a >> b;
a -= 1, b -= 1;
graph[a].push_back(b);
graph[b].push_back(a);
}
const auto bfs = [&](const int src) {
vector<int> dist(N, -1);
std::queue<int> que;
const auto push = [&](const int u, const int d) {
if (dist[u] == -1) {
dist[u] = d;
que.push(u);
}
};
push(src, 0);
while (!que.empty()) {
const int u = que.front();
que.pop();
for (const int v : graph[u]) {
push(v, dist[u] + 1);
}
}
return dist;
};
const auto dist0 = bfs(0);
const int L = std::max_element(dist0.begin(), dist0.end()) - dist0.begin();
const auto distL = bfs(L);
const int R = std::max_element(distL.begin(), distL.end()) - distL.begin();
const int D = distL[R];
const auto distR = bfs(R);
vector<int> path(D + 1);
for (int i = 0; i < N; ++i) {
if (distL[i] + distR[i] > D + 4) {
std::cout << "NO\n";
return 0;
}
if (distL[i] + distR[i] == D) {
path[distL[i]] = i;
}
}
if (D <= 2) {
const int cen = path[D / 2] + 1;
std::cout << "YES\n2\n";
std::cout << cen << ' ' << cen << '\n';
return 0;
}
vector<int> ans;
for (int i = 1; i < D; ++i) {
const int u = path[i];
ans.push_back(u);
for (const int v : graph[u]) {
if (graph[v].size() > 1 and distL[v] + distR[v] > D) {
ans.push_back(v);
ans.push_back(u);
}
}
}
for (int i = D - 1; i > 0; --i) {
const int u = path[i];
ans.push_back(u);
for (const int v : graph[u]) {
if (graph[v].size() > 1 and distL[v] + distR[v] > D) {
ans.push_back(v);
ans.push_back(u);
}
}
}
std::cout << "YES\n";
const int n = ans.size();
std::cout << n << '\n';
for (int i = 0; i < n; ++i) {
std::cout << ans[i] + 1 << " \n"[i + 1 == n];
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
0 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
204 KB |
Output is correct |
8 |
Correct |
1 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
312 KB |
Output is correct |
10 |
Correct |
1 ms |
204 KB |
Output is correct |
11 |
Correct |
1 ms |
316 KB |
Output is correct |
12 |
Correct |
0 ms |
204 KB |
Output is correct |
13 |
Correct |
0 ms |
204 KB |
Output is correct |
14 |
Correct |
0 ms |
204 KB |
Output is correct |
15 |
Correct |
1 ms |
204 KB |
Output is correct |
16 |
Correct |
1 ms |
204 KB |
Output is correct |
17 |
Correct |
1 ms |
204 KB |
Output is correct |
18 |
Correct |
1 ms |
312 KB |
Output is correct |
19 |
Correct |
0 ms |
204 KB |
Output is correct |
20 |
Correct |
1 ms |
204 KB |
Output is correct |
21 |
Correct |
1 ms |
204 KB |
Output is correct |
22 |
Correct |
1 ms |
204 KB |
Output is correct |
23 |
Correct |
1 ms |
312 KB |
Output is correct |
24 |
Correct |
0 ms |
308 KB |
Output is correct |
25 |
Correct |
0 ms |
204 KB |
Output is correct |
26 |
Correct |
1 ms |
204 KB |
Output is correct |
27 |
Correct |
1 ms |
204 KB |
Output is correct |
28 |
Correct |
0 ms |
204 KB |
Output is correct |
29 |
Correct |
1 ms |
204 KB |
Output is correct |
30 |
Correct |
0 ms |
204 KB |
Output is correct |
31 |
Correct |
0 ms |
204 KB |
Output is correct |
32 |
Correct |
1 ms |
316 KB |
Output is correct |
33 |
Correct |
0 ms |
204 KB |
Output is correct |
34 |
Correct |
1 ms |
204 KB |
Output is correct |
35 |
Correct |
1 ms |
204 KB |
Output is correct |
36 |
Correct |
1 ms |
204 KB |
Output is correct |
37 |
Correct |
0 ms |
204 KB |
Output is correct |
38 |
Correct |
1 ms |
204 KB |
Output is correct |
39 |
Correct |
1 ms |
308 KB |
Output is correct |
40 |
Correct |
1 ms |
204 KB |
Output is correct |
41 |
Correct |
0 ms |
204 KB |
Output is correct |
42 |
Correct |
0 ms |
204 KB |
Output is correct |
43 |
Correct |
0 ms |
204 KB |
Output is correct |
44 |
Correct |
1 ms |
204 KB |
Output is correct |
45 |
Correct |
1 ms |
204 KB |
Output is correct |
46 |
Correct |
1 ms |
204 KB |
Output is correct |
47 |
Correct |
1 ms |
204 KB |
Output is correct |
48 |
Correct |
1 ms |
312 KB |
Output is correct |
49 |
Correct |
1 ms |
204 KB |
Output is correct |
50 |
Correct |
1 ms |
204 KB |
Output is correct |
51 |
Correct |
0 ms |
204 KB |
Output is correct |
52 |
Correct |
1 ms |
204 KB |
Output is correct |
53 |
Correct |
0 ms |
204 KB |
Output is correct |
54 |
Correct |
0 ms |
204 KB |
Output is correct |
55 |
Correct |
0 ms |
204 KB |
Output is correct |
56 |
Correct |
1 ms |
204 KB |
Output is correct |
57 |
Correct |
1 ms |
204 KB |
Output is correct |
58 |
Correct |
1 ms |
204 KB |
Output is correct |
59 |
Correct |
1 ms |
204 KB |
Output is correct |
60 |
Correct |
1 ms |
204 KB |
Output is correct |
61 |
Correct |
1 ms |
204 KB |
Output is correct |
62 |
Correct |
1 ms |
204 KB |
Output is correct |
63 |
Correct |
1 ms |
312 KB |
Output is correct |
64 |
Correct |
1 ms |
204 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
204 KB |
Output is correct |
8 |
Correct |
1 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
1 ms |
204 KB |
Output is correct |
11 |
Correct |
1 ms |
348 KB |
Output is correct |
12 |
Correct |
1 ms |
332 KB |
Output is correct |
13 |
Correct |
1 ms |
332 KB |
Output is correct |
14 |
Correct |
1 ms |
332 KB |
Output is correct |
15 |
Correct |
1 ms |
332 KB |
Output is correct |
16 |
Correct |
1 ms |
332 KB |
Output is correct |
17 |
Correct |
1 ms |
332 KB |
Output is correct |
18 |
Correct |
1 ms |
332 KB |
Output is correct |
19 |
Correct |
1 ms |
332 KB |
Output is correct |
20 |
Correct |
1 ms |
332 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
204 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
204 KB |
Output is correct |
5 |
Correct |
0 ms |
204 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
204 KB |
Output is correct |
8 |
Correct |
1 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
312 KB |
Output is correct |
10 |
Correct |
1 ms |
204 KB |
Output is correct |
11 |
Correct |
1 ms |
316 KB |
Output is correct |
12 |
Correct |
0 ms |
204 KB |
Output is correct |
13 |
Correct |
0 ms |
204 KB |
Output is correct |
14 |
Correct |
0 ms |
204 KB |
Output is correct |
15 |
Correct |
1 ms |
204 KB |
Output is correct |
16 |
Correct |
1 ms |
204 KB |
Output is correct |
17 |
Correct |
1 ms |
204 KB |
Output is correct |
18 |
Correct |
1 ms |
312 KB |
Output is correct |
19 |
Correct |
0 ms |
204 KB |
Output is correct |
20 |
Correct |
1 ms |
204 KB |
Output is correct |
21 |
Correct |
1 ms |
204 KB |
Output is correct |
22 |
Correct |
1 ms |
204 KB |
Output is correct |
23 |
Correct |
1 ms |
312 KB |
Output is correct |
24 |
Correct |
0 ms |
308 KB |
Output is correct |
25 |
Correct |
0 ms |
204 KB |
Output is correct |
26 |
Correct |
1 ms |
204 KB |
Output is correct |
27 |
Correct |
1 ms |
204 KB |
Output is correct |
28 |
Correct |
0 ms |
204 KB |
Output is correct |
29 |
Correct |
1 ms |
204 KB |
Output is correct |
30 |
Correct |
0 ms |
204 KB |
Output is correct |
31 |
Correct |
0 ms |
204 KB |
Output is correct |
32 |
Correct |
1 ms |
316 KB |
Output is correct |
33 |
Correct |
0 ms |
204 KB |
Output is correct |
34 |
Correct |
1 ms |
204 KB |
Output is correct |
35 |
Correct |
1 ms |
204 KB |
Output is correct |
36 |
Correct |
1 ms |
204 KB |
Output is correct |
37 |
Correct |
0 ms |
204 KB |
Output is correct |
38 |
Correct |
1 ms |
204 KB |
Output is correct |
39 |
Correct |
1 ms |
308 KB |
Output is correct |
40 |
Correct |
1 ms |
204 KB |
Output is correct |
41 |
Correct |
0 ms |
204 KB |
Output is correct |
42 |
Correct |
0 ms |
204 KB |
Output is correct |
43 |
Correct |
0 ms |
204 KB |
Output is correct |
44 |
Correct |
1 ms |
204 KB |
Output is correct |
45 |
Correct |
1 ms |
204 KB |
Output is correct |
46 |
Correct |
1 ms |
204 KB |
Output is correct |
47 |
Correct |
1 ms |
204 KB |
Output is correct |
48 |
Correct |
1 ms |
312 KB |
Output is correct |
49 |
Correct |
1 ms |
204 KB |
Output is correct |
50 |
Correct |
1 ms |
204 KB |
Output is correct |
51 |
Correct |
0 ms |
204 KB |
Output is correct |
52 |
Correct |
1 ms |
204 KB |
Output is correct |
53 |
Correct |
0 ms |
204 KB |
Output is correct |
54 |
Correct |
0 ms |
204 KB |
Output is correct |
55 |
Correct |
0 ms |
204 KB |
Output is correct |
56 |
Correct |
1 ms |
204 KB |
Output is correct |
57 |
Correct |
1 ms |
204 KB |
Output is correct |
58 |
Correct |
1 ms |
204 KB |
Output is correct |
59 |
Correct |
1 ms |
204 KB |
Output is correct |
60 |
Correct |
1 ms |
204 KB |
Output is correct |
61 |
Correct |
1 ms |
204 KB |
Output is correct |
62 |
Correct |
1 ms |
204 KB |
Output is correct |
63 |
Correct |
1 ms |
312 KB |
Output is correct |
64 |
Correct |
1 ms |
204 KB |
Output is correct |
65 |
Correct |
0 ms |
204 KB |
Output is correct |
66 |
Correct |
0 ms |
308 KB |
Output is correct |
67 |
Correct |
1 ms |
204 KB |
Output is correct |
68 |
Correct |
1 ms |
308 KB |
Output is correct |
69 |
Correct |
1 ms |
204 KB |
Output is correct |
70 |
Correct |
1 ms |
312 KB |
Output is correct |
71 |
Correct |
1 ms |
204 KB |
Output is correct |
72 |
Correct |
1 ms |
312 KB |
Output is correct |
73 |
Correct |
1 ms |
204 KB |
Output is correct |
74 |
Correct |
1 ms |
204 KB |
Output is correct |
75 |
Correct |
0 ms |
204 KB |
Output is correct |
76 |
Correct |
1 ms |
204 KB |
Output is correct |
77 |
Correct |
0 ms |
204 KB |
Output is correct |
78 |
Correct |
0 ms |
204 KB |
Output is correct |
79 |
Correct |
1 ms |
316 KB |
Output is correct |
80 |
Correct |
1 ms |
332 KB |
Output is correct |
81 |
Correct |
1 ms |
332 KB |
Output is correct |
82 |
Correct |
1 ms |
316 KB |
Output is correct |
83 |
Correct |
1 ms |
316 KB |
Output is correct |
84 |
Correct |
1 ms |
332 KB |
Output is correct |
85 |
Correct |
1 ms |
332 KB |
Output is correct |
86 |
Correct |
1 ms |
332 KB |
Output is correct |
87 |
Correct |
1 ms |
332 KB |
Output is correct |
88 |
Correct |
1 ms |
332 KB |
Output is correct |
89 |
Correct |
1 ms |
320 KB |
Output is correct |
90 |
Correct |
1 ms |
332 KB |
Output is correct |
91 |
Correct |
1 ms |
332 KB |
Output is correct |
92 |
Correct |
1 ms |
332 KB |
Output is correct |
93 |
Correct |
1 ms |
332 KB |
Output is correct |
94 |
Correct |
1 ms |
344 KB |
Output is correct |
95 |
Correct |
1 ms |
332 KB |
Output is correct |
96 |
Correct |
1 ms |
332 KB |
Output is correct |
97 |
Correct |
1 ms |
332 KB |
Output is correct |
98 |
Correct |
2 ms |
332 KB |
Output is correct |
99 |
Correct |
1 ms |
320 KB |
Output is correct |
100 |
Correct |
1 ms |
332 KB |
Output is correct |
101 |
Correct |
1 ms |
332 KB |
Output is correct |
102 |
Correct |
1 ms |
332 KB |
Output is correct |
103 |
Correct |
1 ms |
332 KB |
Output is correct |
104 |
Correct |
1 ms |
332 KB |
Output is correct |
105 |
Correct |
2 ms |
316 KB |
Output is correct |
106 |
Correct |
1 ms |
332 KB |
Output is correct |
107 |
Correct |
1 ms |
332 KB |
Output is correct |
108 |
Correct |
1 ms |
332 KB |
Output is correct |
109 |
Correct |
1 ms |
332 KB |
Output is correct |
110 |
Correct |
1 ms |
332 KB |
Output is correct |
111 |
Correct |
1 ms |
336 KB |
Output is correct |
112 |
Correct |
1 ms |
336 KB |
Output is correct |
113 |
Correct |
1 ms |
336 KB |
Output is correct |
114 |
Correct |
1 ms |
332 KB |
Output is correct |
115 |
Correct |
2 ms |
332 KB |
Output is correct |
116 |
Correct |
1 ms |
332 KB |
Output is correct |
117 |
Correct |
2 ms |
384 KB |
Output is correct |
118 |
Correct |
1 ms |
316 KB |
Output is correct |
119 |
Correct |
1 ms |
336 KB |
Output is correct |
120 |
Correct |
1 ms |
336 KB |
Output is correct |
121 |
Correct |
1 ms |
340 KB |
Output is correct |
122 |
Correct |
1 ms |
332 KB |
Output is correct |
123 |
Correct |
1 ms |
332 KB |
Output is correct |
124 |
Correct |
1 ms |
332 KB |
Output is correct |
125 |
Correct |
1 ms |
332 KB |
Output is correct |
126 |
Correct |
1 ms |
332 KB |
Output is correct |
127 |
Correct |
1 ms |
316 KB |
Output is correct |
128 |
Correct |
2 ms |
332 KB |
Output is correct |
129 |
Correct |
1 ms |
332 KB |
Output is correct |
130 |
Correct |
1 ms |
332 KB |
Output is correct |
131 |
Correct |
1 ms |
332 KB |
Output is correct |
132 |
Correct |
1 ms |
320 KB |
Output is correct |
133 |
Correct |
1 ms |
296 KB |
Output is correct |
134 |
Correct |
1 ms |
332 KB |
Output is correct |
135 |
Correct |
1 ms |
332 KB |
Output is correct |
136 |
Correct |
1 ms |
332 KB |
Output is correct |
137 |
Correct |
1 ms |
332 KB |
Output is correct |
138 |
Correct |
1 ms |
332 KB |
Output is correct |
139 |
Correct |
1 ms |
332 KB |
Output is correct |
140 |
Correct |
1 ms |
324 KB |
Output is correct |
141 |
Correct |
1 ms |
332 KB |
Output is correct |
142 |
Correct |
1 ms |
332 KB |
Output is correct |
143 |
Correct |
1 ms |
336 KB |
Output is correct |
144 |
Correct |
2 ms |
332 KB |
Output is correct |
145 |
Correct |
1 ms |
332 KB |
Output is correct |