Submission #367540

#	Time	Username	Problem	Language	Result	Execution time	Memory
367540		ACmachine	Railway (BOI17_railway)	C++17	100 / 100	259 ms	36444 KiB

railway

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

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

template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;

typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<str> vstr;

#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back 
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define rsz resize 
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)
	
const double EPS = 1e-9;
const int MOD = 1e9+7; // 998244353;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};

#ifdef DEBUG
#define DBG if(1)
#else
#define DBG if(0)
#endif

#define dbg(x) cout << "(" << #x << " : " << x << ")" << endl;
// ostreams
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "[";  REP(i, v.size()) out << v[i] << ", ";  out << "]"; return out;}
// istreams
template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }
template<class T, class U>
istream& operator>>(istream& in, pair<T, U> &p){ in >> p.ff >> p.ss; return in; }
//searches
template<typename T, typename U>
T bsl(T lo, T hi, U f){ hi++; T mid; while(lo < hi){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid+1; } return lo; }
template<typename U>
double bsld(double lo, double hi, U f, double p = 1e-9){ int r = 3 + (int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid; } return (lo + hi)/2; }
template<typename T, typename U>
T bsh(T lo, T hi, U f){ lo--; T mid; while(lo < hi){ mid = (lo + hi + 1)/2; f(mid) ? lo = mid : hi = mid-1; } return lo; }
template<typename U>
double bshd(double lo, double hi, U f, double p = 1e-9){ int r = 3+(int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? lo = mid : hi = mid; } return (lo + hi)/2; }
// some more utility functions
template<typename T>
pair<T, int> get_min(vector<T> &v){ typename vector<T> :: iterator it = min_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T>
pair<T, int> get_max(vector<T> &v){ typename vector<T> :: iterator it = max_element(v.begin(), v.end()); return mp(*it, it - v.begin());}        
template<typename T> bool ckmin(T& a, const T& b){return b < a ? a = b , true : false;}
template<typename T> bool ckmax(T& a, const T& b){return b > a ? a = b, true : false;}

    
int main(){
 	ios_base::sync_with_stdio(false);
 	cin.tie(NULL); cout.tie(NULL);
	int n, m, k;
    cin >> n >> m >> k;
    vector<vector<array<int, 2>>> g(n);
    vector<int> ans(n - 1, 0); // how many times is the edge requested
    REP(i, n -1){
        int u, v;
        cin >> u >> v;
        u--; v--;
        g[u].pb({v, i});
        g[v].pb({u, i});
    }
    const int mx = 19;
    vector<vector<int>> nxt(n, vector<int>(mx, -1));
    vector<int> lev(n, 0);
    vector<int> in(n);
    vector<int> out(n);
    int t = 0;
    function<void(int, int)> dfs =  [&](int v, int p){
        in[v] = t; t++;
        if(p != -1) 
            lev[v] = lev[p] + 1;
        nxt[v][0] = p;
        FOR(i, 1, mx, 1){
            if(nxt[v][i - 1] != -1){
                nxt[v][i] = nxt[nxt[v][i - 1]][i - 1];
            }
        }   
        for(auto x : g[v]){
            if(x[0] == p) continue;
            dfs(x[0], v); 
        }
        out[v] = t;
    };
    dfs(0, -1);
    auto lca = [&](int u, int v){
        if(lev[u] < lev[v]) swap(u, v);
        REPD(i, mx - 1){
            if(lev[u] - (1 << i) >= lev[v])
                u = nxt[u][i];
        }
        if(u == v) return u;
        REPD(i, mx - 1){
            if(nxt[u][i] != nxt[v][i]){
                u = nxt[u][i];
                v = nxt[v][i];
            }
        }
        return nxt[u][0];
    };
    vector<vector<int>> vg(n);
    auto build_virtual_tree = [&](vector<int> &vert){
        auto cmp = [&](int u, int v){
            return in[u] < in[v];
        };
        auto upper = [&](int u, int v){
            return (in[u] <= in[v] && out[u] >= out[v]);
        };
        sort(all(vert), cmp);
        int up = (int)vert.size() - 1;
        REP(i, up){
            vert.pb(lca(vert[i], vert[i + 1]));
        }
        sort(all(vert), cmp);
        vert.erase(unique(all(vert)), vert.end());
        for(int x : vert) 
            vg[x].clear();  
        vector<int> st;
        st.pb(vert[0]);
        FOR(i, 1, vert.size(), 1){
            while(st.size() >= 2 && !upper(st.back(), vert[i])){
                int u = st[(int)st.size() - 1]; int v = st[(int)st.size() - 2];
                vg[u].pb(v);
                vg[v].pb(u);
                st.pop_back();
            }
            st.push_back(vert[i]);
        }
        while(st.size() >= 2){
            int u = st[(int)st.size() - 1]; int v = st[(int)st.size() - 2];
            vg[u].pb(v);
            vg[v].pb(u);
            st.pop_back();
        }
        return st[0];
    };
    vector<int> lazy(n, 0);
    auto add_on_path = [&](int u, int v){
        lazy[u]++; lazy[v]++;
        lazy[lca(u, v)]-=2;
    };
    auto propagate_lazy = [&](){
        vector<int> st;
        queue<int> q;
        q.push(0); st.push_back(0);
        vector<bool> visited(n, false);
        visited[0] = true;
        while(!q.empty()){
            int v = q.front();
            q.pop();
            for(auto x : g[v]){
                if(!visited[x[0]]){
                    visited[x[0]] = true;
                    q.push(x[0]);
                    st.push_back(x[0]);
                }
            }
        }
        while(!st.empty()){
            int v = st.back();
            st.pop_back();
            int par = nxt[v][0];
            lazy[par] += lazy[v];
            for(auto x : g[v]){
                if(x[0] == par)
                    ans[x[1]] += lazy[v];
            }
        }
    };
    vector<int> vert;
    REP(i, m){
        int ns; cin >> ns;
        vert.clear();
        REP(j, ns){
            int s; cin >> s;
            s--;
            vert.pb(s);
        }
        int root = build_virtual_tree(vert);
        function<void(int, int)> go = [&](int v, int p){
            for(int x : vg[v]){
                if(x == p) continue;
                add_on_path(v, x);
                go(x, v);
            }
        };
        go(root, -1);
    }
    propagate_lazy();
    vector<int> res;
    REP(i, n - 1){
        if(ans[i] >= k) 
            res.pb(i);
    }
    cout << res.size() << "\n";
    REP(j, res.size()){
        cout << res[j] + 1 << (j == (int)res.size() - 1 ? "\n" : " ");
    }
    return 0;
}

Compilation message (stderr)

railway.cpp: In lambda function:
railway.cpp:26:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 | #define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
      |                                        ^
railway.cpp:156:9: note: in expansion of macro 'FOR'
  156 |         FOR(i, 1, vert.size(), 1){
      |         ^~~
railway.cpp: In function 'int main()':
railway.cpp:26:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 | #define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
      |                                        ^
railway.cpp:28:18: note: in expansion of macro 'FOR'
   28 | #define REP(i,b) FOR(i,0,b,1)
      |                  ^~~
railway.cpp:232:5: note: in expansion of macro 'REP'
  232 |     REP(j, res.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