제출 #828277

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
828277		Evirir	Cat Exercise (JOI23_ho_t4)	C++17	100 / 100	262 ms	55736 KiB

Main

#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
#define watch(x) cout<<(#x)<<"="<<(x)<<'\n'
#define mset(d,val) memset(d,val,sizeof(d))
#define cbug if(DEBUG) cout
#define setp(x) cout<<fixed<<setprecision(x)
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define forn(i,a,b) for(int i=(a);i<(b);i++)
#define fore(i,a,b) for(int i=(a);i<=(b);i++)
#define pb push_back
#define F first
#define S second
#define fbo find_by_order
#define ook order_of_key
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> ii;
typedef vector<ll> vi;
typedef vector<ii> vii;
//template<typename T>
//using pbds = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
void SD(int t=0){ cout<<"PASSED "<<t<<endl; }
ostream& operator<<(ostream &out, ii x){ out<<"("<<x.F<<","<<x.S<<")"; return out; }
template<typename T> void amax(T &a, T b){ a=max(a,b); }
template<typename T> void amin(T &a, T b){ a=min(a,b); }
struct Hash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }
    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

const ll INF = ll(1e18);
const int MOD = 998244353;
const bool DEBUG = 0;
const int MAXN = 200005;
const int LG = 21;

struct DSU {
	struct Node{ int p, sz, mx; };
	vector<Node> dsu; int cc;
	Node& operator[](int id){ return dsu[rt(id)]; }
	DSU(int n){ dsu.resize(n);
		forn(i,0,n){ cc=n; dsu[i]={i,1,i}; }
	}
	inline int rt(int u){ return (dsu[u].p==u) ? u : dsu[u].p=rt(dsu[u].p); }
	inline bool sameset(int u, int v){ return rt(u)==rt(v); }
	void merge(int u, int v){
		u = rt(u); v = rt(v);
		if(u == v) return;
		if(dsu[u].sz < dsu[v].sz) swap(u,v);
		dsu[v].p = u;
		dsu[u].sz += dsu[v].sz;
        dsu[u].mx = max(dsu[u].mx, dsu[v].mx);
		cc--;
	}
};

vector<vector<int>> adj;
vector<ll> dist;
vector<ll> dp;
vector<bool> vst;

int in[MAXN],out[MAXN],tmr=-1;
int prt[LG][MAXN];
int dep[MAXN];

void dfs_lca(int u, int p)
{
	in[u]=++tmr;
	prt[0][u]=p;
	forn(i,1,LG){
		if(prt[i-1][u]!=-1) prt[i][u]=prt[i-1][prt[i-1][u]];
	}
	for(int v: adj[u]){
		if(v==p) continue;
        dep[v] = dep[u] + 1;
		dfs_lca(v,u);
	}
	out[u]=tmr;
}
bool isChild(int u, int v)
{
	return in[u]<=in[v] && out[v]<=out[u];
}
int getLca(int u, int v)
{
	if(isChild(u,v)) return u;
	for(int i=LG-1;i>=0;i--){
		if(prt[i][u]!=-1 && !isChild(prt[i][u],v))
			u=prt[i][u];
	}
	return prt[0][u];
}

int main()
{
    cin.tie(0)->sync_with_stdio(0);
    mset(prt,-1);

    int n; cin>>n;
    adj.resize(n);
    dp.resize(n, 0);
    vst.resize(n, 0);
    dist.resize(n);

    int p[n];
    forn(i,0,n)
    {
        cin>>p[i];
        p[i]--;
    }
    forn(i,0,n-1)
    {
        int u,v; cin>>u>>v; u--; v--;
        u=p[u];
        v=p[v];
        adj[u].pb(v);
        adj[v].pb(u);
    }

    dfs_lca(0, -1);
    DSU dsu(n);
    forn(u,0,n)
    {
        for (int v : adj[u])
        {
            if (v > u) continue;
            int mx = dsu[v].mx;
            int dist = dep[u] + dep[mx] - 2 * dep[getLca(u, mx)];
            dp[u] = max(dp[u], dp[mx] + dist);
        }
        for (int v : adj[u])
        {
            if (v > u) continue;
            dsu.merge(u, v);
        }
    }

    cout<<dp[n-1]<<'\n';

    return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 7 / 7
• Subtask 4: 10 / 10
• Subtask 5: 20 / 20
• Subtask 6: 23 / 23
• Subtask 7: 26 / 26