제출 #799782

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
799782		Alish	Mergers (JOI19_mergers)	C++14	100 / 100	911 ms	136088 KiB

mergers

#include <bits/stdc++.h>

using namespace std;

typedef long long int	ll;
typedef long double	ld;
typedef pair<int, int>	pii;
typedef pair<ll, ll>	pll;


#define F		        first
#define S		        second
#define pb		        push_back
#define endl            '\n'
#define Mp		        make_pair
#define all(x)          x.begin(), x.end()
#define debug(x)        cerr << #x << " = " << x << endl
#define set_dec(x)	    cout << fixed << setprecision(x);
#define fast_io         ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io         freopen("in.txt" , "r+" , stdin) ; freopen("out.txt" , "w+" , stdout);


ll mod = 998244353;

ll power(ll a, ll b)
{
    return (!b ? 1 : (b & 1 ? a * power(a * a % mod, b / 2) % mod : power(a * a % mod, b / 2) % mod));
}

const int N = 5e5+23, L =23 ;

vector<int>g[N], buc[N];
int st[N], h[N], par[N][L], sz[N], sum[N], is[N];
int ans;
int n , k ;
int a[N];

int tim;
void dfs(int v, int p=0){
    sz[v]=1;
    st[v]=++tim;
    for (int u: g[v]) {
        if(u==p)continue;
        h[u]=h[v]+1;
        par[u][0]=v;
        dfs(u,v);
        sz[v]+=sz[u];
    }
}

void DFS(int v, int p=0){

    int temp=0;
    for (int u: g[v]){
        if(u==p) continue;
        DFS(u,v);
        is[v]+=is[u];
        sum[v]+=sum[u];
    }

    if(sum[v]==sz[v]){
        if(is[v]==0 && v!=1)ans++;
        if(is[v]==1 && v==1) ans++;
        is[v]=1;
    }
}

int LCA(int v, int u){

    if(h[v]>h[u])swap(u,v);

    int d =h[u]-h[v];
    for (int i=L-1; i>=0; i--) {
        if(d>>i&1) u=par[u][i];
    }

    if(u==v) return v;

    for (int i=L-1; i>=0; i--){
        if(par[u][i]!=par[v][i]){
            v=par[v][i];
            u=par[u][i];
        }
    }

    return par[v][0];

}

int main()
{
    fast_io
    cin>>n>>k;
    for (int i=0; i<n-1; i++){
        int u , v; cin>>v>>u;
        g[v].pb(u);
        g[u].pb(v);
    }
    for (int i=1; i<=n; i++){
        cin>>a[i];
        buc[a[i]].pb(i);
    }

    dfs(1);

    for (int j=1; j<L; j++){
        for (int i=1; i<=n; i++){
            par[i][j]=par[par[i][j-1]][j-1];
        }
    }

    for (int w=1; w<=k; w++){
        vector<pii> vec;
        for (int i: buc[w]) vec.pb({st[i], i});
        sort(all(vec));
        int lca=LCA(vec[0].S, vec.back().S);
        sum[lca]+=buc[w].size();
    }

    DFS(1);

    //cout<<ans<<" ";
    cout<<(ans+1)/2<<endl;

}

컴파일 시 표준 에러 (stderr) 메시지

mergers.cpp: In function 'void DFS(int, int)':
mergers.cpp:53:9: warning: unused variable 'temp' [-Wunused-variable]
   53 |     int temp=0;
      |         ^~~~

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