Submission #500855

#	Time	Username	Problem	Language	Result	Execution time	Memory
500855		MohamedAliSaidane	Railway (BOI17_railway)	C++14	100 / 100	507 ms	36020 KiB

railway

#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef tuple<int,int,int> ti;
typedef unsigned long long ull;
typedef long double ld;
typedef vector<ll> vll;
typedef pair<ld,ld> pld;
#define pb push_back
#define popb pop_back()
#define pf push_front
#define popf pop_front
#define ff first
#define ss second
#define MOD (ll)(1000000007)
#define INF (ll) (1e18)
#define all(v) (v).begin(),(v).end()
const int nx[8] = {0, 0, 1, -1,1,1,-1,-1}, ny[8] = {1, -1, 0, 0,1,-1,1,-1}; //East, West, South, North+
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;}
ll lcm(ll a, ll b){return (a / gcd(a, b)) * b;}
////////////******SOLUTION******\\\\\\\\\\\

const int MAX_N = 2e5 + 4;;

int n, m, k, sz = 1;
vi adj[MAX_N];
int heavy[MAX_N];
vi st, lazy;
int p[MAX_N];
int head[MAX_N];
int subtree[MAX_N];
int d[MAX_N];
int eul[MAX_N];
int cur_eul = -1;
map<pii,int> key;
bool comp(int a, int b)
{
    return eul[a] < eul[b];
}
void propagate(int p, int l, int r)
{
    if(lazy[p] != 0)
    {
        st[p] += lazy[p] * (r-l+1);
        if(l != r)
        {
            lazy[2*p] += lazy[p];
            lazy[2*p+1] += lazy[p];
        }
        lazy[p] = 0;
    }
}
int query(int p, int l, int r, int i, int j)
{
    propagate(p,l,r);
    if( i > j)
        return 0;
    if(l >= i && r <= j)
        return st[p];
    int mid = (l+r)/2;
    return query(2*p,l,mid,i,min(mid,j))
        + query(2*p+1,mid+1,r,max(i,mid+1),j);
}
void update(int p, int l, int r, int i, int j, int val)
{
    propagate(p,l,r);
    if(i > j )
        return ;
    if(l >= i && r <= j)
    {
        lazy[p] += val;
        propagate(p,l,r);
    }
    else
    {
        int mid = (l+r)/2;
        update(2*p,l,mid,i,min(j,mid),val);
        update(2*p+1,mid+1,r,max(i,mid+1),j,val);
        int lsubtree = (lazy[2*p] * (r-l+1))/2 + st[2*p];
        int rsubtree = (lazy[2*p+1] * (r-l+1))/2 + st[2*p+1];
        st[p] = lsubtree + rsubtree;
    }
}
void dfs(int x, int par)
{
    d[x] = d[par] + 1;
    p[x] = par;
    subtree[x] = 1;
    for(auto e: adj[x])
    {
        if(e == par) continue;
        dfs(e,x);
        subtree[x] += subtree[e];
        if(subtree[e] > subtree[heavy[x]])
            heavy[x] = e;
    }
}
void decompose(int x, int h)
{
    head[x] = h;
    eul[x] = ++cur_eul;
    if(heavy[x] != 0)
        decompose(heavy[x],h);
    for(auto e: adj[x])
    {
        if(e != p[x] && e != heavy[x])
        {
            decompose(e,e);
        }
    }
}
void upd(int a, int b)
{
    for(;head[a] != head[b]; b = p[head[b]])
    {
        if(d[head[a]] > d[head[b]])
            swap(a,b);
        update(1,0,sz-1,eul[head[b]],eul[b],1);
    }
    if(d[a] > d[b])
        swap(a,b);
    update(1,0,sz-1,eul[a]+1,eul[b],1);
    return ;
}
void solve()
{
    cin >> n >> m >> k;
    while(sz < n) sz = (sz << 1);
    st.assign(2*sz+1,0);
    lazy.assign(2*sz+1,0);
    for(int i = 1; i <n; i ++)
    {
        int a,b;
        cin >> a >> b;
        adj[a].pb(b);
        adj[b].pb(a);
        key[{a,b}] = key[{b,a}] = i;
    }
    d[0] = -1;
    dfs(1,0);
    decompose(1,1);
    for(int i = 1; i<= m; i ++)
    {
        int s; cin >> s;
        int nodes[s];
        for(int j = 0; j <s; j ++)
            cin >> nodes[j];
        sort(nodes,nodes+s,comp);
        for(int j = 0; j <s; j ++)
        {
            int u =nodes[j];
            int v = nodes[(j+1)%s];
            upd(u,v);
        }
    }
    vi ans;
    for(int i=  2; i <=n; i ++)
    {
        int val = query(1,0,sz-1,eul[i],eul[i]);
        if(val >= 2*k)
        {
            ans.pb(key[{i,p[i]}]);
        }
    }
    sort(all(ans));
    cout << ans.size() << '\n';
    for(auto e: ans)
        cout << e << ' ';
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    int tt =1;
    while(tt--)
    {
        solve();
    }

}
/*

*/

Compilation message (stderr)

railway.cpp:24:1: warning: multi-line comment [-Wcomment]
   24 | ////////////******SOLUTION******\\\\\\\\\\\
      | ^

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