Submission #825959

#	Time	Username	Problem	Language	Result	Execution time	Memory
825959		fdnfksd	Parkovi (COCI22_parkovi)	C++14	110 / 110	1373 ms	38372 KiB

Main

#include <bits/stdc++.h>
#define taskname "cargroup"
using namespace std;
#define int long long
typedef long long ll;
typedef pair<int,int> pli;
typedef unsigned long long ull;
#define fi first
#define se second
#define pb push_back

#define faster ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
const ll maxN=2e5+10;
// a la thg chon gan nhat
// b la thg ko thoa man xa nhat
ll a[maxN],b[maxN];
const ll inf=1e15;
vector<pli>g[maxN];
#define fi first
#define se second
ll cnt=0;
vector<ll>trace;
bool in[maxN];
void dfs(ll u,ll p,ll mid)
{
    a[u]=inf;
    b[u]=0;
    for(auto vv:g[u])
    {
        int v=vv.fi;
        int w=vv.se;
        if(v==p) continue;
        dfs(v,u,mid);
    }
    for(auto vv:g[u])
    {
        int v=vv.fi;
        int w=vv.se;
        if(v==p) continue;
        if(b[v]!=-1&&b[v]+w>mid)
        {
            trace.pb(v);
            in[v]=true;
            cnt++;
            a[v]=0;
            a[u]=min(a[u],w);
            b[v]=-1;
        }
        else
        {
            if(b[v]!=-1) b[u]=max(b[u],b[v]+w);
            a[u]=min(a[u],a[v]+w);
        }
    }
    if(a[u]+b[u]<=mid)
    {
        b[u]=-1;
    }
    if(u==1&&b[1]!=-1)
    {
        cnt++;
        trace.pb(1);
        in[1]=true;
    }
}
ll k,n;
bool check(ll mid)
{
    trace.clear();
    for(int i=1;i<=n;i++) in[i]=false;
    cnt=0;
    dfs(1,0,mid);
    return cnt<=k;
}
//ll n;
void solve()
{
    cin >> n >> k;
    for(int i=1;i<n;i++)
    {
        ll u,v,w;
        cin >> u >> v >> w;
        g[u].pb({v,w});
        g[v].pb({u,w});
    }
    ll low=0,high=3e14;
    while(low<=high)
    {
        ll mid=low+high>>1;
        if(check(mid)) high=mid-1;
        else low=mid+1;
    }
    cout << low<<'\n';
    check(low);
    for(int i=1;i<=n;i++)
    {
        if(in[i]==false&&trace.size()<k) trace.pb(i),in[i]=true;
    }
    for(auto zz:trace) cout << zz<<' ';
}
signed main()
{
    faster
//   freopen(taskname".INP","r",stdin);
//    freopen(taskname".OUT","w",stdout);
    solve();
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'void dfs(ll, ll, ll)':
Main.cpp:31:13: warning: unused variable 'w' [-Wunused-variable]
   31 |         int w=vv.se;
      |             ^
Main.cpp: In function 'void solve()':
Main.cpp:89:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   89 |         ll mid=low+high>>1;
      |                ~~~^~~~~
Main.cpp:97:38: warning: comparison of integer expressions of different signedness: 'std::vector<long long int>::size_type' {aka 'long unsigned int'} and 'll' {aka 'long long int'} [-Wsign-compare]
   97 |         if(in[i]==false&&trace.size()<k) trace.pb(i),in[i]=true;
      |                          ~~~~~~~~~~~~^~

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