D.cpp

/****************************** begin /template.h ******************************/

/***********************************************************************
 * [?] APIO 2021 Template
 * [+] Made By: Lior Yehezkely, FiveSixFiveFour
 * [~] Apples are ORZ
 * *********************************************************************/

/*** begin #define flags ***/
// #define USE_ORDERED_STATISTICS
// #define BIG_BIGINT
/*** end #define flags ***/

/*** begin includes ***/
#include <bits/stdc++.h>

#ifdef USE_ORDERED_STATISTICS
    #include <ext/pb_ds/assoc_container.hpp>
    #include <ext/pb_ds/tree_policy.hpp>
    using namespace __gnu_pbds;
#endif

using namespace std;
/*** end includes ***/

/*** begin typedefs ***/
typedef long long int ll;
#ifdef BIG_BIGINT
    typedef __int128_t bigint;
#else
    typedef ll bigint;
#endif
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<vpi> vvpi;
typedef vector<vpl> vvpl;
typedef set<int> si;
typedef multiset<int> msi;
typedef set<ll> sl;
typedef multiset<ll> msl;
typedef long double ld;
template<class T> using func = function<T>;

#ifdef USE_ORDERED_STATISTICS
    typedef tree<
    pl,
    null_type,
    less<pl>,
    rb_tree_tag,
    tree_order_statistics_node_update>
    ordered_set;
#endif

/*** end typedefs ***/

/*** begin #defines ***/
#define clrcin cin.ignore(numeric_limits<streamsize>::max(),'\n');
#define GOGOGO ios::sync_with_stdio(false); cin.tie(nullptr);
#define BYEBYE return 0;

#define all(cn) (cn).begin(), (cn).end()
#define rep(i, n) for (int i = 0; i < n; ++i)
#define csz(c) ((int)c.size())
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define fi first
#define se second

#define popcnt __builtin_popcount
#define popcntll __builtin_popcount_ll

/*** end #defines ***/

const int INFI = 1e9 + 5;
const ll INFL = 1e18 + 5;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count()); 
auto dist = uniform_int_distribution<int>(0, INFI); 
auto distll = uniform_int_distribution<ll>(0, INFL); 
int rnd() { return dist(rng); }
ll rndl() { return distll(rng); }

/****************************** end /template.h ******************************/


/****************************** begin /main.cpp ******************************/


/*** begin #define flags ***/
#define BRUH_WHY_TESTCASES
//#define PREC 7
//#define INPUT_FILE "hi.in"
//#define OUTPUT_FILE "hi.out"
/*** end #define flags ***/

const int maxn = 3e5 + 5;



vector<int> ans[maxn];
int par[maxn];

vi g[maxn];
int n;
int root;
int path_root[maxn];
int path_count = 0;
void dfs(int c, int p=-1, bool new_path=true) {
    if(new_path) {
        path_count++;
        path_root[c] = c;
        ans[path_root[c]].pb(c);
    } else {
        path_root[c] = path_root[p];
        ans[path_root[c]].pb(c);
    }
    bool child_use_new_path = false;
    for(auto e : g[c]) {
        if(e != p) {
            dfs(e, c, child_use_new_path);
            child_use_new_path = true;
        }
    }
}

void clean() {
    rep(i, n+1) {
        ans[i] = vi();
        path_root[i] = -1;
        par[i] = -1;
        g[i] = vi();
    }
    root = -1;
    n = -1;
    path_count = 0;
}

void solve(int t) {
    cin >> n;
    rep(i, n){
        cin >> par[i+1];
        if(par[i+1] == i + 1) {
            root = i + 1;
        } else {
            g[i+1].pb(par[i+1]);
            g[par[i+1]].pb(i+1);
        }
    }
    dfs(root);
    cout << path_count << '\n';
    for(int i = 1; i <= n; i++) {
        if(ans[i].size()) {
            cout << ans[i].size() << '\n';
            for(const auto& e : ans[i]) {
                cout << e << ' ';
            }
            cout << '\n';
        }
    }
    clean();
    
}











































signed main()
{
    #ifdef INPUT_FILE
        freopen(INPUT_FILE, "r", stdin);
    #endif
    #ifdef OUTPUT_FILE
        freopen(OUTPUT_FILE, "w", stdout);
    #endif
    GOGOGO
    #ifdef PREC
      cout << fixed << setprecision(PREC);
    #endif
    int t=1;
    #ifdef BRUH_WHY_TESTCASES
            cin >> t;
    #endif

    int count = 1;
    while(t--)
    {
        //cout << "Case #" << count << ":";
        solve(count);
        count += 1;
    }
    BYEBYE
}

/* PLEASE READ THIS
* N = 1
* GUESS A!!!!!!!
* DO SOMETHING INSTEAD OF NOTHING
*/

/****************************** end /main.cpp ******************************/