Submission #648268

#	Time	Username	Problem	Language	Result	Execution time	Memory
648268		smirichto	Race (IOI11_race)	C++17	21 / 100	701 ms	21180 KiB

race

/*
    STAY ORGANIZED
    CHANGE YOUR APPROACH
*/
#include<bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef long double ld ;
#define FAST ios::sync_with_stdio(0), cin.tie(0),cout.tie(0)
#define pb push_back
#define pi pair<ll,ll>
#define pll pair<ll,ll>
#define yes cout<<"Yes"<<endl;
#define no cout<<"No"<<endl;
#define flag cout<<"hi"<<endl;
#define fr(i,a,b) for(ll i = a;i < (ll)b;i++)
#define rfr(i,a,b) for(ll i = a;i > (ll)b;i--)
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
#define alll(x) ((x).begin()+1), (x).end()
#define MOD mod
#define endl '\n'
const ll mod = 1e9+7 ;
void io(){ios::sync_with_stdio(false) ;cin.tie(NULL) ;//freopen("grader.in.4","r",stdin) ;//freopen("problem1.out","w",stdout) ;
}
void dbg(vector<ll> tab){for(auto it : tab) cout<<it<<" ";cout<<endl;}
void dbgg(pi p){cout<<p.F<<" "<<p.S<<endl;}
void dbgpi(vector<pi> tab){for(auto it : tab) dbgg(it) ;}
template<class T> bool ckmax(T& a, const T& b){return a < b ? a = b, 1 : 0;}
template<class T> bool ckmin(T& a, const T& b){return a > b ? a = b, 1 : 0;}
template<class T> void add(T& a, const T& b){a = a + b ; if(a>mod) a-= mod ;}
void nop(){cout<<-1<<endl;return;}
#define forr(i, x, y)   for(ll i = x; i <= y; i++)
const ll inf = 1e9 +1;
const ll N = 5e5+5 ;

ll _n , _k ;
vector<pi> v[N] ;
ll len[N] , sz[N] , vis[N] ;

void get_sz(ll node , ll oj)
{
    sz[node] = 1 ;
    for(auto [it,i] : v[node]){
        if(it==oj || vis[it]) continue ;
        get_sz(it,node) ;
        sz[node] += sz[it] ;
    }
}

ll get_centro(ll node , ll oj , ll m)
{
    for(auto [it,i] : v[node]){
        if(!vis[it] && it!=oj && sz[it]>m/2) return get_centro(it,node,m) ;
    }
    return node ;
}
map<ll,ll> mp , exist ;
ll ans = 1e11 ;

void get_cnt(ll node , ll oj , ll ok , ll curr_len, ll d = 1)
{
//    cout<<node<<" "<<curr_len<<endl;
    if(ok){
        if(_k-curr_len>=0 && exist[_k-curr_len]){
//            cout<<node<<" "<<d<<" "<<k-curr_len<<endl;
            ckmin(ans, d+mp[_k-curr_len]) ;
        }
    }
    else{
        if(exist[curr_len]) ckmin(mp[curr_len] , d) ;
        else{
            mp[curr_len] = d;
            exist[curr_len] = 1 ;
        }
    }
    for(auto [it,i] : v[node]){
        if(vis[it] || it==oj) continue ;
        get_cnt(it,node,ok,curr_len+len[i],d+1) ;
    }
}

void build(ll node = 0)
{
    get_sz(node , node) ;
    ll centroid = get_centro(node , node , sz[node]) ;

    mp.clear() ;
    exist.clear() ;
//    cout<<centroid<<endl;
    vis[centroid] = 1 ;
    for(auto [it,i] : v[centroid]){
        get_cnt(it,node,1 , len[i]) ;
        get_cnt(it,node,0 , len[i]) ;
    }


    for(auto [it,i] : v[centroid]){
        if(!vis[it]) build(it) ;
    }
}

//void solve()
//{
////    cin>>n>>k ;
////    for(ll i = 1 ; i<n ; i++){
////        ll x , y ; cin>>x>>y ;
////        v[x].pb({y,i}) ;
////        v[y].pb({x,i}) ;
////    }
////
////    for(ll i = 1 ; i<n ; i++) cin>>len[i] ;
//    build() ;
////    cout<<ans<<endl;
//}
ll best_path(int n, int k, int edges[][2], int weights[])
{
	if (k == 1)
	{
		return 0;
	}
	_n = n;
	_k = k;
	ans = 1e11 ;
	for (ll i = 1; i < n ; i++)
	{
		ll x = edges[i-1][0];
		ll y = edges[i-1][1];
		v[x].pb(pi(y, i));
		v[y].pb(pi(x, i));
		len[i] = weights[i-1] ;
	}
	build() ;
	return ans >= (1e11) ? -1 : ans;
}

// ll main()
//{
//    io() ;
//    srand(time(0)) ;
//    ll tt = 1 ;
////    cin>>tt ;
//    for(ll i = 1 ; i<=tt ; i++){
//        solve() ;
//    }
//}



/*
11 12

0 1
0 2
2 3
3 4
4 5
0 6
6 7
6 8
8 9
8 10

3
4
5
4
6
3
2
5
6
7

*/

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57