Submission #1050856

#	Time	Username	Problem	Language	Result	Execution time	Memory
1050856		Jarif_Rahman	Mergers (JOI19_mergers)	C++17	100 / 100	470 ms	74944 KiB

mergers

#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;

int n, k;
vector<vector<int>> tree;
vector<int> sz;
vector<int> state, scnt;
vector<int> cnt;
int bsc = 0;
vector<bool> sep;
int sep_cnt = 0;

void pre_dfs(int nd, int ss){
    for(int x: tree[nd]) if(x != ss) pre_dfs(x, nd), sz[nd]+=sz[x];
}

void add(int nd, int ss){
    cnt[state[nd]]++;
    if(cnt[state[nd]] == 1) bsc++;
    if(cnt[state[nd]] == scnt[state[nd]]) bsc--;
    for(int x: tree[nd]) if(x != ss) add(x, nd);
}
void remove(int nd, int ss){
    cnt[state[nd]]--;
    if(cnt[state[nd]] == scnt[state[nd]]-1) bsc++;
    if(cnt[state[nd]] == 0) bsc--;
    for(int x: tree[nd]) if(x != ss) remove(x, nd);
}
void dfs(int nd, int ss, bool keep){
    int bigchild = -1, bigchild_size = -1;
    for(int x: tree[nd]) if(x != ss && sz[x] > bigchild_size) bigchild_size = sz[x], bigchild = x;
    for(int x: tree[nd]) if(x != ss && x != bigchild) dfs(x, nd, 0);
    if(bigchild != -1) dfs(bigchild, nd, 1);

    cnt[state[nd]]++;
    if(cnt[state[nd]] == 1) bsc++;
    if(cnt[state[nd]] == scnt[state[nd]]) bsc--;
    for(int x: tree[nd]) if(x != ss && x != bigchild) add(x, nd);
    if(ss != -1 && bsc == 0) sep[nd] = 1;
    if(sep[nd]) sep_cnt++;

    if(keep) return;
    cnt[state[nd]]--;
    if(cnt[state[nd]] == scnt[state[nd]]-1) bsc++;
    if(cnt[state[nd]] == 0) bsc--;
    for(int x: tree[nd]) if(x != ss) remove(x, nd);
}

int ans = 0;
bool exta = 0;
int dfs2(int nd, int ss, int sep_cnt_ = 0){
    int c = 0;
    for(int x: tree[nd]) if(x != ss) c+=dfs2(x, nd, sep_cnt_+sep[nd]);
    if(ss == -1) return 0;
    if(!sep[nd]) return c;
    c++;
    if(c == 1) ans++;
    else if(c+sep_cnt_ == sep_cnt) exta = 1;
    return c;
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> k;
    tree.resize(n);
    sz.resize(n, 1);
    state.resize(n);
    scnt.resize(k, 0);
    cnt.resize(k, 0);
    sep.resize(n, 0);

    for(int i = 0; i < n-1; i++){
        int a, b; cin >> a >> b; a--, b--;
        tree[a].push_back(b);
        tree[b].push_back(a);
    }
    for(int i = 0; i < n; i++){
        cin >> state[i]; state[i]--;
        scnt[state[i]]++;
    }

    pre_dfs(0, -1);
    dfs(0, -1, 1);
    dfs2(0, -1);
    ans+=exta;
    ans++;
    ans/=2;
    cout << ans << "\n";
}

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