Submission #788766

#	Time	Username	Problem	Language	Result	Execution time	Memory
788766		TB_	Railway (BOI17_railway)	C++17	100 / 100	260 ms	75304 KiB

railway

#include <bits/stdc++.h>
using namespace std;

// #undef _GLIBCXX_DEBUG                // disable run-time bound checking, etc
// #pragma GCC optimize("Ofast,inline") // Ofast = O3,fast-math,allow-store-data-races,no-protect-parens
// #pragma GCC optimize ("unroll-loops")

// #pragma GCC target("bmi,bmi2,lzcnt,popcnt")                      // bit manipulation
#pragma GCC target("movbe")                                      // byte swap
// #pragma GCC target("aes,pclmul,rdrnd")                           // encryption
// #pragma GCC target("avx,avx2,f16c,fma,sse3,ssse3,sse4.1,sse4.2") // SIMD

// #include <bits/extc++.h>
// using namespace __gnu_pbds;
// template<class T>using ordered_set = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
// template<class T>using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define ll long long
#define INF (ll)1e9+7
#define fo(i, n) for(int i=0;i<n;i++)
#define deb(x) cout << #x << " = " << x << endl;
#define deb2(x, y) cout << #x << " = " << x << ", " << #y << " = " << y << endl
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define LSOne(S) ((S) & (-S))
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
inline int readint(){ int v = 0; char c; while((c = getchar()) != EOF && c != ' ' && c != '\n'){ v *= 10; v += c - '0'; } return v; }
inline int readintsigned() { int v = 0; int sign = 1; char c = getchar(); if (c == '-') { sign = -1; } else { v += c - '0'; } while ((c = getchar()) != EOF && c != ' ' && c != '\n') { v *= 10; v += c - '0'; } return v * sign; }
inline string readstring() { string s; char c; while ((c = getchar()) != EOF && c != '\n' && c != ' ') { s.push_back(c); } return s; }
template <class result_t=std::chrono::milliseconds,class clock_t=std::chrono::steady_clock,class duration_t = std::chrono::milliseconds>
auto since(std::chrono::time_point<clock_t, duration_t> const& start){return std::chrono::duration_cast<result_t>(clock_t::now() - start);}
typedef pair<int, int> pii;
typedef pair<ll, ll> pl;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpii;
typedef vector<pl> vpl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<vpii> vvpii;
typedef vector<vpl> vvpl;

vvi adj(100001);
vl d(100001);
vpl order;

void dfs(int pos, int last = -1, int depth = 0){
    d[pos] = depth;
    for(auto u : adj[pos]){
        if(u == last) continue;
        dfs(u, pos, depth+1);
    }
    order.pb({depth, pos});
}

int main() {
    // cout << fixed << setprecision(20);
    // auto start = std::chrono::steady_clock::now(); // since(start).count()
    cin.tie(0)->sync_with_stdio(0);

    int n, m, k, a, val, from, to;
    cin >> n >> m >> k;

    map<pl, ll> toRoad;
    fo(i, n-1){
        cin >> from >> to;
        adj[--from].pb(--to);
        adj[to].pb(from);
        toRoad[{from, to}] = i+1;
        toRoad[{to, from}] = i+1;
    }

    dfs(0);
    vvl bl(24, vl(100001, 0));
    fo(i, adj.size()){
        for(auto v : adj[i]){
            if(d[v] >= d[i]) continue;
            bl[0][i] = v;
        }
    }
    fo(i, 22){
        fo(j, n){
            bl[i+1][j] = bl[i][bl[i][j]];
        }
    }

    vvl root(100001);
    vector<set<ll>> wantRoad(100001);

    fo(x, m){
        cin >> a;
        vl v;
        fo(y, a){
            cin >> val;
            val--;
            v.pb(val);
            wantRoad[val].insert(x);
        }
        ll deapest = v[0];
        fo(i, a){
            if(!i) continue;
            ll current = v[i];
            if(d[current]<d[deapest]) swap(deapest, current);
            for(int m = d[current]-d[deapest];m;m-=LSOne(m)){
                current = bl[__builtin_ctz(LSOne(m))][current];
            }
            if(current == deapest) continue;
            for(int j = 22; j>=0;j--){
                if(bl[j][current] == bl[j][deapest]) continue;
                current = bl[j][current];
                deapest = bl[j][deapest];
            }
            current = bl[0][current];
            deapest = bl[0][deapest];
        }
        root[deapest].pb(x);
    }

    vl ans;

    sort(rall(order));

    for(auto ver : order){
        if(!ver.S) continue;
        for(auto toRem :  root[ver.S]){
            wantRoad[ver.S].erase(toRem);
        }
        if(wantRoad[ver.S].size() >= k) ans.pb(toRoad[{ver.S, bl[0][ver.S]}]);
        if(wantRoad[ver.S].size() > wantRoad[bl[0][ver.S]].size()) swap(wantRoad[ver.S], wantRoad[bl[0][ver.S]]);
        for(auto ve :  wantRoad[ver.S]){
            wantRoad[bl[0][ver.S]].insert(ve);
        }
    }
    sort(all(ans));
    cout << ans.size() << "\n";
    fo(i, ans.size()){
        cout << ans[i] << " ";
    }

    return 0;
}

Compilation message (stderr)

railway.cpp: In function 'int main()':
railway.cpp:20:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 | #define fo(i, n) for(int i=0;i<n;i++)
......
   78 |     fo(i, adj.size()){
      |        ~~~~~~~~~~~~~           
railway.cpp:78:5: note: in expansion of macro 'fo'
   78 |     fo(i, adj.size()){
      |     ^~
railway.cpp:131:35: warning: comparison of integer expressions of different signedness: 'std::set<long long int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  131 |         if(wantRoad[ver.S].size() >= k) ans.pb(toRoad[{ver.S, bl[0][ver.S]}]);
      |            ~~~~~~~~~~~~~~~~~~~~~~~^~~~
railway.cpp:20:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 | #define fo(i, n) for(int i=0;i<n;i++)
......
  139 |     fo(i, ans.size()){
      |        ~~~~~~~~~~~~~           
railway.cpp:139:5: note: in expansion of macro 'fo'
  139 |     fo(i, ans.size()){
      |     ^~

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 7 / 7
• Subtask 4: 29 / 29
• Subtask 5: 16 / 16
• Subtask 6: 25 / 25