Submission #486580

#	Time	Username	Problem	Language	Result	Execution time	Memory
486580		i_am_noob	Mergers (JOI19_mergers)	C++17	100 / 100	1056 ms	129992 KiB

mergers

#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,popcnt,tune=native")

#define ll long long
//#define int ll
#define ull unsigned ll
#define ld long double
#define rep(a) rep1(i,a)
#define rep1(i,a) rep2(i,0,a)
#define rep2(i,b,a) for(int i=(b); i<((int)(a)); i++)
#define rep3(i,b,a) for(int i=(b); i>=((int)(a)); i--)
#define chkmin(a,b) (a=min(a,b))
#define chkmax(a,b) (a=max(a,b))
#define all(a) a.begin(),a.end()
#define pii pair<int,int>
#define pb push_back
#define inf 1010000000
//#define inf 4000000000000000000
#define eps 1e-9
#define sz(a) ((int)a.size())
#define pow2(x) (1ll<<(x))
#define ceiling(a,b) (((a)+(b)-1)/(b))
#define print0(a) cout << (a) << ' '
#define ykh mt19937 rng(chrono::steady_clock::now().time_since_epoch().count())
#ifdef i_am_noob
#define bug(...) cerr << "#" << __LINE__ << ' ' << #__VA_ARGS__ << "- ", _do(__VA_ARGS__)
template<typename T> void _do(vector<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(set<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(unordered_set<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(T && x) {cerr << x << endl;}
template<typename T, typename ...S> void _do(T && x, S&&...y) {cerr << x << ", "; _do(y...);}
#else
#define bug(...) 777771449
#endif
template<typename T> void print(T && x) {cout << x << "\n";}
template<typename T, typename... S> void print(T && x, S&&... y) {cout << x << ' ';print(y...);}

const int Mod=1000000007,Mod2=998244353;
const int MOD=Mod;
const int maxn=500005,maxm=7777714,maxk=7777714;
    
//i_am_noob
//#define wiwihorz  
int n,k,id[maxn],dep[maxn],par[maxn][20],siz[maxn],val[maxn],stamp,comp[maxn],deg[maxn];
vector<int> adj[maxn],vec[maxn];

void dfs(int u, int fa){
    id[u]=stamp++;
    siz[u]=1;
    par[u][0]=fa;
    dep[u]=fa==-1?0:dep[fa]+1;
    rep2(i,1,20) par[u][i]=par[u][i-1]==-1?-1:par[par[u][i-1]][i-1];
    for(auto v: adj[u]) if(v!=fa){
        dfs(v,u);
        siz[u]+=siz[v];
    }
}

int lca(int u, int v){
    if(dep[u]>dep[v]) swap(u,v);
    rep(20) if((dep[v]-dep[u])>>i&1) v=par[v][i];
    if(u==v) return u;
    rep3(i,19,0) if(par[u][i]!=par[v][i]) u=par[u][i],v=par[v][i];
    return par[u][0];
}

void dfs2(int u, int fa){
    for(auto v: adj[u]) if(v!=fa){
        dfs2(v,u);
        val[u]+=val[v];
    }
}

void dfs3(int u, int fa){
    if(fa!=-1&&siz[u]==val[u]){
        comp[u]=++stamp;
        deg[comp[u]]++;
        deg[comp[fa]]++;
    }
    else comp[u]=fa==-1?0:comp[fa];
    for(auto v: adj[u]) if(v!=fa){
        dfs3(v,u);
    }
}

void orzck(){
    cin >> n >> k;
    rep(n-1){
        int u,v;
        cin >> u >> v;
        u--,v--;
        adj[u].pb(v),adj[v].pb(u);
    }
    rep(n){
        int x;
        cin >> x;
        x--;
        vec[x].pb(i);
    }
    dfs(0,-1);
    rep(k) if(sz(vec[i])){
        int x=vec[i][0];
        for(auto u: vec[i]) x=lca(x,u);
        val[x]+=sz(vec[i]);
        /*
        sort(all(vec[i]),[](int i1, int i2){return id[i1]<id[i2];});
        vector<int> stk;
        stk.pb(0);
        val[0]+=sz(vec[i]);
        for(auto u: vec[i]){
            int x=lca(stk.back(),u);
            val[u]+=sz(vec[i]);
            val[x]-=sz(vec[i]);
            while(dep[stk.back()]>dep[x]) stk.pop_back();
            if(stk.back()!=x) stk.pb(x);
            stk.pb(u);
        }
        */
    }
    dfs2(0,-1);
    stamp=0;
    dfs3(0,-1);
    int res=0;
    rep(stamp+1) if(deg[i]==1) res++;
    print((res+1)/2);
}

signed main(){
    ios_base::sync_with_stdio(0),cin.tie(0);
    #ifdef i_am_noob
    freopen("input1.txt","r",stdin);
    freopen("output1.txt","w",stdout);
    freopen("output2.txt","w",stderr);
    #endif
    cout << fixed << setprecision(15);
    int t;
    #ifdef wiwihorz
    cin >> t;
    #else
    t=1;
    #endif
    while(t--) orzck();
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 24 / 24
• Subtask 3: 14 / 14
• Subtask 4: 22 / 22
• Subtask 5: 30 / 30