#include <bits/extc++.h>
using namespace std;
using namespace __gnu_pbds;
typedef int64_t ll;
typedef long double ld;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define pb emplace_back
#define mp make_pair
#define mt make_tuple
#define pii pair<int,int>
#define F(n) Fi(i,n)
#define Fi(i,n) Fl(i,0,n)
#define Fl(i,l,n) for(int i=l;i<n;i++)
#define RF(n) RFi(i,n)
#define RFi(i,n) RFl(i,0,n)
#define RFl(i,l,n) for(int i=n-1;i>=l;i--)
#define all(v) begin(v),end(v)
#define siz(v) (ll(v.size()))
#define get_pos(v,x) (lower_bound(all(v),x)-begin(v))
#define sort_uni(v) sort(begin(v),end(v)),v.erase(unique(begin(v),end(v)),end(v))
#define mem(v,x) memset(v,x,sizeof v)
#define ff first
#define ss second
#define mid ((l+r)>>1)
#define RAN(a,b) uniform_int_distribution<int> (a, b)(rng)
/*
bool chain = true;
Fl(i, 1, n+1){
if(edges[i].size() > 2){
chain = false;
break;
}
}
if(chain){
printf("YES\n");
printf("%d\n", 2 * (n-2));
F(n-2) printf("%d ", i+2);
if(n%2 == 0) RF(n-2) printf("%d ", i+2);
else F(n-2) printf("%d ", i+2);
}else{
printf("YES\n1\n1");
}
*/
template <typename T> using max_heap = __gnu_pbds::priority_queue<T,less<T> >;
template <typename T> using min_heap = __gnu_pbds::priority_queue<T,greater<T> >;
template <typename T> using rbt = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
const int maxN = 1010;
vector<int> edges[maxN];
bool visited[maxN];
int depth1[maxN], mx_depth1, deepest_node1;
void dfs1(int pos, int fa){ // dfs1 finds one endpoint of the diameter
for(int i : edges[pos]){
if(visited[i] || i == fa) continue;
depth1[i] = depth1[pos] + 1;
if(mx_depth1 < depth1[i]){
mx_depth1 = depth1[i];
deepest_node1 = i;
}
dfs1(i, pos);
}
}
int sz[maxN];
int depth[maxN];
void dfs_sz(int pos, int fa){
sz[pos] = 1;
for(int i : edges[pos]){
if(visited[i] || i == fa) continue;
depth[i] = depth[pos] + 1;
dfs_sz(i, pos);
sz[pos] += sz[i];
}
}
vector<int> tour;
int cnt;
int nn;
void Euler_Tour(int pos, int fa){
tour.pb(pos);
cnt++;
if(cnt == nn) return;
bool danger = false;
for(int i : edges[pos]){
if(visited[i] || i == fa) continue;
if(sz[i] >= 2){
if(!danger){
danger = true;
}else{
printf("NO\n");
exit(0);
}
}
Euler_Tour(i, pos);
if(cnt == nn) return;
tour.pb(pos);
}
}
signed main(){
int n,m;
cin >> n >> m;
nn = n;
F(m){
int x,y;
cin >> x >> y;
edges[x].pb(y);
edges[y].pb(x);
}
if(n == 1){
printf("YES\n1\n1");
exit(0);
}
if(n == 2){
printf("YES\n2\n1 1");
exit(0);
}
if(m == n-1){
F(n) {
if(edges[i+1].size() == 1){
visited[i+1] = true;
nn--;
sz[i+1] = 1000000;
}
}
F(n){
if(!visited[i+1]){
dfs1(i+1, 0);
break;
}
}
int root = deepest_node1;
dfs_sz(root, 0);
Fl(i, 1, n+1){
sort(all(edges[i]), [&](int a, int b){return sz[a] < sz[b];});
}
Euler_Tour(root, 0);
printf("YES\n");
printf("%d\n", 2 * (int)tour.size());
for(int i : tour){
printf("%d ", i);
}
if(tour.size() % 2 == 0) reverse(all(tour));
for(int i : tour){
printf("%d ", i);
}
}else{
printf("NO\n");
}
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
0 ms |
332 KB |
Output is correct |
4 |
Correct |
0 ms |
332 KB |
Output is correct |
5 |
Incorrect |
0 ms |
332 KB |
Integer 0 violates the range [1, 4] |
6 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
324 KB |
Output is correct |
2 |
Correct |
0 ms |
332 KB |
Output is correct |
3 |
Incorrect |
0 ms |
332 KB |
Integer 0 violates the range [1, 3] |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
0 ms |
332 KB |
Output is correct |
4 |
Correct |
0 ms |
332 KB |
Output is correct |
5 |
Incorrect |
0 ms |
332 KB |
Integer 0 violates the range [1, 4] |
6 |
Halted |
0 ms |
0 KB |
- |