oj.uz

Submission #532639

# Submission time Handle Problem Language Result Execution time Memory
532639 2022-03-03T12:32:08 Z qwerasdfzxcl Newspapers (CEOI21_newspapers) C++14
8 / 100
 14 ms 412 KB 
#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;
    }
    //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:55:10: 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:66:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 0 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 Incorrect 0 ms 204 KB Integer -1 violates the range [1, 4]
6 Halted 0 ms 0 KB -

Subtask #2
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 0 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 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 0 ms 204 KB Output is correct
9 Correct 0 ms 204 KB Output is correct
10 Correct 0 ms 204 KB Output is correct
11 Correct 11 ms 404 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 6 ms 332 KB Output is correct
16 Correct 13 ms 332 KB Output is correct
17 Correct 13 ms 412 KB Output is correct
18 Correct 13 ms 412 KB Output is correct
19 Correct 14 ms 408 KB Output is correct
20 Correct 13 ms 408 KB Output is correct

Subtask #3
0.0 / 80.0

# Verdict Execution time Memory Grader output
1 Correct 0 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 Incorrect 0 ms 204 KB Integer -1 violates the range [1, 4]
6 Halted 0 ms 0 KB -