#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
vector<int> adj[1010];
int h[1010], c[1010];
bool L[1010];
void NO(){
printf("NO\n");
exit(0);
}
void dfs0(int s, int pa = -1){
h[s] = 1;
if (pa==-1) c[s] = 0;
L[s] = 1;
for (auto &v:adj[s]) if (v!=pa){
L[s] = 0;
c[v] = c[s] ^ 1;
dfs0(v, s);
h[s] = max(h[s], h[v] + 1);
}
}
int r = -1;
void chk_valid(int n){
for (int i=1;i<=n;i++){
dfs0(i);
int cnt = 0;
for (auto &v:adj[i]) if (h[v]>=3) cnt++;
if (cnt>=3) NO();
if (cnt==2) r = i;
}
}
vector<int> st;
void dfs2(int s, int pa){
if (L[s]) return;
bool flag = 0;
for (auto &v:adj[s]) if (v!=pa && !L[v]){
st.push_back(s);
dfs2(v, s);
flag = 1;
}
if (!flag) st.push_back(s);
}
bool cmp(int x, int y){return h[x] > h[y];}
int main(){
int n, m;
scanf("%d %d", &n, &m);
if (m>n-1) NO();
if (n<=2){
//naive here
if (n==1) printf("YES\n1\n1\n");
else printf("YES\n2\n1 1\n");
return 0;
}
for (int i=0;i<m;i++){
int x, y;
scanf("%d %d", &x, &y);
adj[x].push_back(y);
adj[y].push_back(x);
}
chk_valid(n);
if (r==-1){
for (int i=1;i<=n;i++) if (adj[i].size()>=2) r = i;
}
assert(r!=-1);
//printf("R = %d\n", r);
dfs0(r);
for (int i=1;i<=n;i++) sort(adj[i].begin(), adj[i].end(), cmp);
if (adj[r].size()>=2 && h[adj[r][1]]>=3) swap(adj[r][1], adj[r].back());
for (int i=1;i<=n;i++) reverse(adj[i].begin(), adj[i].end());
vector<int> ans;
for (auto &v:adj[r]){
if (h[v]>=3 && v==adj[r].back() && (ans.empty() || ans.back()!=r)) ans.push_back(r);
st.clear();
dfs2(v, r);
if (h[v]>=3 && v!=adj[r].back()) reverse(st.begin(), st.end());
for (auto &x:st) ans.push_back(x);
if (h[v]==2 || (h[v]>=3 && v!=adj[r].back())){
ans.push_back(r);
//printf("asdf\n");
}
}
if (ans.empty()) ans.push_back(r);
bool inv = (c[ans[0]]!=c[ans.back()]);
printf("YES\n");
printf("%d\n", (int)ans.size()*2);
for (auto &x:ans) printf("%d ", x);
if (inv) reverse(ans.begin(), ans.end());
for (auto &x:ans) printf("%d ", x);
return 0;
}
Compilation message
newspapers.cpp: In function 'int main()':
newspapers.cpp:55:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
55 | scanf("%d %d", &n, &m);
| ~~~~~^~~~~~~~~~~~~~~~~
newspapers.cpp:66:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
66 | scanf("%d %d", &x, &y);
| ~~~~~^~~~~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
324 KB |
Output is correct |
4 |
Correct |
1 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
312 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
320 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
1 ms |
332 KB |
Output is correct |
10 |
Correct |
1 ms |
320 KB |
Output is correct |
11 |
Correct |
1 ms |
204 KB |
Output is correct |
12 |
Correct |
1 ms |
204 KB |
Output is correct |
13 |
Correct |
1 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 |
320 KB |
Output is correct |
17 |
Correct |
1 ms |
204 KB |
Output is correct |
18 |
Correct |
1 ms |
320 KB |
Output is correct |
19 |
Correct |
1 ms |
204 KB |
Output is correct |
20 |
Correct |
1 ms |
332 KB |
Output is correct |
21 |
Correct |
0 ms |
204 KB |
Output is correct |
22 |
Correct |
1 ms |
204 KB |
Output is correct |
23 |
Correct |
1 ms |
320 KB |
Output is correct |
24 |
Correct |
1 ms |
204 KB |
Output is correct |
25 |
Correct |
0 ms |
332 KB |
Output is correct |
26 |
Correct |
0 ms |
204 KB |
Output is correct |
27 |
Correct |
1 ms |
220 KB |
Output is correct |
28 |
Correct |
1 ms |
288 KB |
Output is correct |
29 |
Correct |
0 ms |
320 KB |
Output is correct |
30 |
Correct |
1 ms |
204 KB |
Output is correct |
31 |
Correct |
1 ms |
204 KB |
Output is correct |
32 |
Correct |
1 ms |
204 KB |
Output is correct |
33 |
Correct |
1 ms |
204 KB |
Output is correct |
34 |
Correct |
1 ms |
204 KB |
Output is correct |
35 |
Correct |
1 ms |
332 KB |
Output is correct |
36 |
Correct |
1 ms |
316 KB |
Output is correct |
37 |
Correct |
1 ms |
204 KB |
Output is correct |
38 |
Correct |
1 ms |
332 KB |
Output is correct |
39 |
Correct |
1 ms |
332 KB |
Output is correct |
40 |
Correct |
1 ms |
204 KB |
Output is correct |
41 |
Correct |
0 ms |
320 KB |
Output is correct |
42 |
Correct |
1 ms |
316 KB |
Output is correct |
43 |
Correct |
1 ms |
204 KB |
Output is correct |
44 |
Correct |
0 ms |
204 KB |
Output is correct |
45 |
Correct |
0 ms |
204 KB |
Output is correct |
46 |
Correct |
1 ms |
320 KB |
Output is correct |
47 |
Correct |
1 ms |
204 KB |
Output is correct |
48 |
Correct |
1 ms |
204 KB |
Output is correct |
49 |
Correct |
1 ms |
320 KB |
Output is correct |
50 |
Correct |
1 ms |
204 KB |
Output is correct |
51 |
Correct |
1 ms |
204 KB |
Output is correct |
52 |
Correct |
1 ms |
204 KB |
Output is correct |
53 |
Correct |
1 ms |
204 KB |
Output is correct |
54 |
Correct |
1 ms |
204 KB |
Output is correct |
55 |
Correct |
1 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 |
316 KB |
Output is correct |
62 |
Correct |
1 ms |
316 KB |
Output is correct |
63 |
Correct |
1 ms |
316 KB |
Output is correct |
64 |
Correct |
0 ms |
204 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
0 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
204 KB |
Output is correct |
4 |
Correct |
1 ms |
332 KB |
Output is correct |
5 |
Correct |
1 ms |
204 KB |
Output is correct |
6 |
Correct |
1 ms |
332 KB |
Output is correct |
7 |
Correct |
1 ms |
204 KB |
Output is correct |
8 |
Correct |
1 ms |
216 KB |
Output is correct |
9 |
Correct |
1 ms |
320 KB |
Output is correct |
10 |
Correct |
0 ms |
332 KB |
Output is correct |
11 |
Correct |
13 ms |
336 KB |
Output is correct |
12 |
Correct |
4 ms |
332 KB |
Output is correct |
13 |
Correct |
5 ms |
332 KB |
Output is correct |
14 |
Correct |
6 ms |
332 KB |
Output is correct |
15 |
Correct |
7 ms |
320 KB |
Output is correct |
16 |
Correct |
13 ms |
332 KB |
Output is correct |
17 |
Correct |
14 ms |
332 KB |
Output is correct |
18 |
Correct |
14 ms |
416 KB |
Output is correct |
19 |
Correct |
16 ms |
416 KB |
Output is correct |
20 |
Correct |
14 ms |
332 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
204 KB |
Output is correct |
3 |
Correct |
1 ms |
324 KB |
Output is correct |
4 |
Correct |
1 ms |
204 KB |
Output is correct |
5 |
Correct |
1 ms |
312 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
0 ms |
320 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
1 ms |
332 KB |
Output is correct |
10 |
Correct |
1 ms |
320 KB |
Output is correct |
11 |
Correct |
1 ms |
204 KB |
Output is correct |
12 |
Correct |
1 ms |
204 KB |
Output is correct |
13 |
Correct |
1 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 |
320 KB |
Output is correct |
17 |
Correct |
1 ms |
204 KB |
Output is correct |
18 |
Correct |
1 ms |
320 KB |
Output is correct |
19 |
Correct |
1 ms |
204 KB |
Output is correct |
20 |
Correct |
1 ms |
332 KB |
Output is correct |
21 |
Correct |
0 ms |
204 KB |
Output is correct |
22 |
Correct |
1 ms |
204 KB |
Output is correct |
23 |
Correct |
1 ms |
320 KB |
Output is correct |
24 |
Correct |
1 ms |
204 KB |
Output is correct |
25 |
Correct |
0 ms |
332 KB |
Output is correct |
26 |
Correct |
0 ms |
204 KB |
Output is correct |
27 |
Correct |
1 ms |
220 KB |
Output is correct |
28 |
Correct |
1 ms |
288 KB |
Output is correct |
29 |
Correct |
0 ms |
320 KB |
Output is correct |
30 |
Correct |
1 ms |
204 KB |
Output is correct |
31 |
Correct |
1 ms |
204 KB |
Output is correct |
32 |
Correct |
1 ms |
204 KB |
Output is correct |
33 |
Correct |
1 ms |
204 KB |
Output is correct |
34 |
Correct |
1 ms |
204 KB |
Output is correct |
35 |
Correct |
1 ms |
332 KB |
Output is correct |
36 |
Correct |
1 ms |
316 KB |
Output is correct |
37 |
Correct |
1 ms |
204 KB |
Output is correct |
38 |
Correct |
1 ms |
332 KB |
Output is correct |
39 |
Correct |
1 ms |
332 KB |
Output is correct |
40 |
Correct |
1 ms |
204 KB |
Output is correct |
41 |
Correct |
0 ms |
320 KB |
Output is correct |
42 |
Correct |
1 ms |
316 KB |
Output is correct |
43 |
Correct |
1 ms |
204 KB |
Output is correct |
44 |
Correct |
0 ms |
204 KB |
Output is correct |
45 |
Correct |
0 ms |
204 KB |
Output is correct |
46 |
Correct |
1 ms |
320 KB |
Output is correct |
47 |
Correct |
1 ms |
204 KB |
Output is correct |
48 |
Correct |
1 ms |
204 KB |
Output is correct |
49 |
Correct |
1 ms |
320 KB |
Output is correct |
50 |
Correct |
1 ms |
204 KB |
Output is correct |
51 |
Correct |
1 ms |
204 KB |
Output is correct |
52 |
Correct |
1 ms |
204 KB |
Output is correct |
53 |
Correct |
1 ms |
204 KB |
Output is correct |
54 |
Correct |
1 ms |
204 KB |
Output is correct |
55 |
Correct |
1 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 |
316 KB |
Output is correct |
62 |
Correct |
1 ms |
316 KB |
Output is correct |
63 |
Correct |
1 ms |
316 KB |
Output is correct |
64 |
Correct |
0 ms |
204 KB |
Output is correct |
65 |
Correct |
1 ms |
204 KB |
Output is correct |
66 |
Correct |
0 ms |
204 KB |
Output is correct |
67 |
Correct |
0 ms |
204 KB |
Output is correct |
68 |
Correct |
1 ms |
204 KB |
Output is correct |
69 |
Correct |
0 ms |
204 KB |
Output is correct |
70 |
Correct |
1 ms |
204 KB |
Output is correct |
71 |
Correct |
0 ms |
204 KB |
Output is correct |
72 |
Correct |
1 ms |
332 KB |
Output is correct |
73 |
Correct |
1 ms |
332 KB |
Output is correct |
74 |
Correct |
0 ms |
316 KB |
Output is correct |
75 |
Correct |
1 ms |
204 KB |
Output is correct |
76 |
Correct |
0 ms |
204 KB |
Output is correct |
77 |
Correct |
1 ms |
204 KB |
Output is correct |
78 |
Correct |
0 ms |
204 KB |
Output is correct |
79 |
Correct |
1 ms |
332 KB |
Output is correct |
80 |
Correct |
1 ms |
320 KB |
Output is correct |
81 |
Correct |
1 ms |
332 KB |
Output is correct |
82 |
Correct |
1 ms |
320 KB |
Output is correct |
83 |
Correct |
1 ms |
332 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 |
320 KB |
Output is correct |
87 |
Correct |
1 ms |
332 KB |
Output is correct |
88 |
Correct |
1 ms |
332 KB |
Output is correct |
89 |
Correct |
17 ms |
376 KB |
Output is correct |
90 |
Correct |
15 ms |
376 KB |
Output is correct |
91 |
Correct |
16 ms |
368 KB |
Output is correct |
92 |
Correct |
13 ms |
368 KB |
Output is correct |
93 |
Correct |
16 ms |
368 KB |
Output is correct |
94 |
Correct |
10 ms |
332 KB |
Output is correct |
95 |
Correct |
18 ms |
376 KB |
Output is correct |
96 |
Correct |
18 ms |
384 KB |
Output is correct |
97 |
Correct |
10 ms |
332 KB |
Output is correct |
98 |
Correct |
18 ms |
384 KB |
Output is correct |
99 |
Correct |
12 ms |
332 KB |
Output is correct |
100 |
Correct |
13 ms |
380 KB |
Output is correct |
101 |
Correct |
12 ms |
332 KB |
Output is correct |
102 |
Correct |
12 ms |
332 KB |
Output is correct |
103 |
Correct |
15 ms |
324 KB |
Output is correct |
104 |
Correct |
9 ms |
332 KB |
Output is correct |
105 |
Correct |
11 ms |
332 KB |
Output is correct |
106 |
Correct |
15 ms |
324 KB |
Output is correct |
107 |
Correct |
14 ms |
368 KB |
Output is correct |
108 |
Correct |
18 ms |
380 KB |
Output is correct |
109 |
Correct |
13 ms |
324 KB |
Output is correct |
110 |
Correct |
13 ms |
332 KB |
Output is correct |
111 |
Correct |
11 ms |
332 KB |
Output is correct |
112 |
Correct |
11 ms |
376 KB |
Output is correct |
113 |
Correct |
17 ms |
384 KB |
Output is correct |
114 |
Correct |
18 ms |
332 KB |
Output is correct |
115 |
Correct |
15 ms |
332 KB |
Output is correct |
116 |
Correct |
15 ms |
376 KB |
Output is correct |
117 |
Correct |
17 ms |
332 KB |
Output is correct |
118 |
Correct |
14 ms |
332 KB |
Output is correct |
119 |
Correct |
12 ms |
320 KB |
Output is correct |
120 |
Correct |
14 ms |
332 KB |
Output is correct |
121 |
Correct |
20 ms |
376 KB |
Output is correct |
122 |
Correct |
17 ms |
324 KB |
Output is correct |
123 |
Correct |
11 ms |
332 KB |
Output is correct |
124 |
Correct |
16 ms |
384 KB |
Output is correct |
125 |
Correct |
9 ms |
332 KB |
Output is correct |
126 |
Correct |
11 ms |
376 KB |
Output is correct |
127 |
Correct |
10 ms |
368 KB |
Output is correct |
128 |
Correct |
16 ms |
384 KB |
Output is correct |
129 |
Correct |
1 ms |
324 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 |
344 KB |
Output is correct |
133 |
Correct |
1 ms |
332 KB |
Output is correct |
134 |
Correct |
1 ms |
324 KB |
Output is correct |
135 |
Correct |
0 ms |
320 KB |
Output is correct |
136 |
Correct |
1 ms |
320 KB |
Output is correct |
137 |
Correct |
1 ms |
204 KB |
Output is correct |
138 |
Correct |
1 ms |
204 KB |
Output is correct |
139 |
Correct |
1 ms |
332 KB |
Output is correct |
140 |
Correct |
1 ms |
320 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 |
12 ms |
312 KB |
Output is correct |
145 |
Correct |
13 ms |
332 KB |
Output is correct |