Submission #696686

#	Time	Username	Problem	Language	Result	Execution time	Memory
696686		Tuanlinh123	Parkovi (COCI22_parkovi)	C++17	10 / 110	77 ms	16500 KiB

Main

#include<bits/stdc++.h>
#define ll long long
#define ld long double
#define pll pair<ll,ll>
#define mp make_pair
#define pb push_back
#define fi first
#define se second

using namespace std;

#define LOCALIO "C:/Users/admin/Documents/Code/"

ll n, k;
ll dis[200005], deg[100005];
bool print[200005];
vector <pll> Line;
vector <pll> A[200005];
priority_queue <pll, vector <pll>, greater <pll>> q;

ll maxdis(ll mask)
{
    for (ll i=0; i<n; i++)
        dis[i]=1e18;
    for (ll i=0; i<n; i++)
        if (mask&1<<i)
            q.push({0, i}), dis[i]=0;
    while (!q.empty())
    {
        ll u=q.top().se, disu=q.top().fi; q.pop();
        if (dis[u]!=disu)
            continue;
        for (pll child:A[u])
        {
            ll v=child.fi, w=child.se;
            if (dis[v]>disu+w)
            {
                dis[v]=disu+w;
                q.push({dis[v], v});
            }
        }
    }
    ll Max=0;
    for (ll i=0; i<n; i++)
        Max=max(Max, dis[i]);
    return Max;
}

void straighten(ll u, ll pre, ll dis)
{
    Line.pb({u, dis});
    if (deg[u]==1)
        return;
    if (A[u][0].fi==pre)
        straighten(A[u][1].fi, u, A[u][1].se);
    else straighten(A[u][0].fi, u, A[u][0].se);
}

bool check(ll mid)
{
    ll cnt=0, crr=0;
    bool has=0;
    for (ll i=0; i<n; i++)
    {
        if (crr+Line[i].se>mid)
        {
            cnt++, crr=-mid;
            if (!has)
                has=1, crr+=Line[i].se;
        }
        else crr+=Line[i].se;
    }
    if (crr>0) cnt++;
    if (cnt>k) return 0;
    return 1;
}

void trace(ll mid)
{
    ll cnt=0, crr=0;
    bool has=0;
    for (ll i=0; i<n; i++)
    {
        if (crr+Line[i].se>mid)
        {
            cout << Line[i-1].fi+1 << " ";
            print[Line[i-1].fi]=1;
            cnt++; crr=-mid;
            if (!has)
                has=1, crr+=Line[i].se;
        }
        else crr+=Line[i].se;
    }
    if (crr>0) cnt++, cout << Line.back().fi+1 << " ", print[Line.back().se]=1;
    for (ll i=0; i<n; i++)
    {
        if (cnt==k)
            break;
        if (!print[i])
        {
            cnt++;
            cout << i+1 << " ";
        }
    }
}

int main()
{
    #ifdef LOCAL
        freopen( LOCALIO "input.txt","r",stdin) ;
        freopen( LOCALIO "output.txt","w",stdout) ;
    #endif

    ios_base::sync_with_stdio(NULL); cin.tie(nullptr); cout.tie(nullptr);
//	freopen("FIBONACCI.inp","r",stdin);
//	freopen("FIBONACCI.out","w",stdout);
    cin >> n >> k;
    bool line=1;
    for (ll i=1; i<n; i++)
    {
        ll u, v, w; cin >> u >> v >> w;
        u--; v--; deg[u]++; deg[v]++;
        if (deg[u]>2 || deg[v]>2) line=0;
        A[u].pb({v, w}); A[v].pb({u, w});
    }
    if (n<=20)
    {
        pll Min={1e18, 0};
        for (ll mask=0; mask<1<<n; mask++)
            if (__builtin_popcount(mask)==k)
                Min=min(Min, {maxdis(mask), mask});
        cout << Min.fi << "\n";
        for (ll i=0; i<n; i++)
            if (Min.se&1<<i)
                cout << i+1 << " ";
        return 0;
    }
    // if (line)
    // {
    //     ll root=0;
    //     for (ll i=0; i<n; i++)
    //         if (deg[i]==1)
    //             root=i;
    //     Line.pb({root, 0});
    //     straighten(A[root][0].fi, root, A[root][0].se);
    //     ll lo=0, hi=1e15;
    //     while (hi-lo>1)
    //     {
    //         ll mid=(lo+hi)/2;
    //         if (check(mid))
    //             hi=mid;
    //         else lo=mid;
    //     }
    //     if (check(lo))
    //     {
    //         cout << lo << "\n";
    //         trace(lo);
    //     }
    //     else
    //     {
    //         cout << hi << "\n";
    //         trace(hi);
    //     }
    //     return 0;
    // }
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:118:10: warning: variable 'line' set but not used [-Wunused-but-set-variable]
  118 |     bool line=1;
      |          ^~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 60