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  1. #include <bits/stdc++.h>
  2. #define FOR(i,start,end,jump) for(int i=(start),_end=(end);i<=_end;i+=(jump))
  3. #define fi first
  4. #define se second
  5. #define ps(any) push_back(any)
  6. using namespace std;
  7.  
  8. const int maxn = 2003;
  9.  
  10. int n, m, x, y, k;
  11. vector<vector<int>> a;
  12. bool visited[maxn], isused[maxn][maxn];
  13. vector<int> res[maxn], tam;
  14.  
  15. void READ(){
  16.     ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
  17.     cin>>n>>m;
  18.     a.resize(n+1);
  19.     FOR(i,1,m,1){
  20.         cin>>x>>y;
  21.         a[x].ps(y);
  22.         a[y].ps(x);
  23.     }
  24. //    FOR(i,1,n,1) sort(a[i].begin(),a[i].end());
  25. }
  26.  
  27. bool dfs(int v,int p)
  28. {
  29.     visited[v] = true;
  30.     tam.ps(v);
  31.     for(int j:a[v]){
  32.         if(j != p){
  33.             if(!visited[j]){
  34.                 dfs(j,v);
  35.             }
  36.             else{
  37.                 int cnt = 0;
  38.                 if(!isused[v][j]){
  39.                     cnt++;
  40.                     isused[v][j] = isused[j][v] = true;
  41.                 }
  42.                 int temp = tam.back();
  43.                 for(int t = tam.size()-2;t>=0;t--){
  44.                     if(!isused[temp][tam[t]]) cnt++;
  45.                     isused[temp][tam[t]] = isused[tam[t]][temp] = true;
  46.                     temp = tam[t];
  47.                 }
  48.                 if(cnt>0)
  49.                 {
  50.                     k++;
  51.                     res[k].ps(j);
  52.                     for(int t=tam.size()-1;t>=0 && tam[t]!=j; t--) res[k].ps(tam[t]);
  53.                     res[k].ps(j);
  54.                 }
  55.             }
  56.         }
  57.     }
  58.     visited[v] = false;
  59.     tam.pop_back();
  60. }
  61. void DO(){
  62.     FOR(i,1,n,1){
  63.         dfs(i,0);
  64.     }
  65.     cout<<k<<'\n';
  66.     FOR(i,1,k,1){
  67.         for(int j = res[i].size()-1;j>=0;j--) cout<<res[i][j]<<" ";
  68.         cout<<'\n';
  69.     }
  70. }
  71.  
  72. int main()
  73. {
  74.     READ();
  75.     DO();
  76. }
  77.  
Success #stdin #stdout 0s 5300KB
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https://ideone.com/Y0PTP0
language:
C++14 (gcc 8.3)
created:
4 days ago
visibility:
public

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