Submission #1271327

#	Time	Username	Problem	Language	Result	Execution time	Memory
1271327		trandangquang	Synchronization (JOI13_synchronization)	C++20	100 / 100	79 ms	18248 KiB

synchronization

#include <bits/stdc++.h>
using namespace std;

#define foru(i,a,b) for(int i=(a); i<=(b); ++i)
#define ford(i,a,b) for(int i=(a); i>=(b); --i)
#define rep(i,a) for(int i=0; i<(a); ++i)
#define bit(s,i) (((s)>>(i))&1)
#define all(a) (a).begin(),(a).end()
#define sz(a) (int)(a).size()
#define ii pair<int,int>
#define fi first
#define se second
#define eb emplace_back
#define pb push_back
#define ll long long
#define __builtin_popcount(a) __builtin_popcountll(a)

template <class X, class Y> bool maxi(X &x, Y y){return x<y?x=y,true:false;}
template <class X, class Y> bool mini(X &x, Y y){return x>y?x=y,true:false;}

const int N=1e5+5;

int n,m,q;
vector<int> adj[N];
ii edge[N];
int sz[N],h[N],par[N];

void pre(int u, int p=-1){
    sz[u]=1;
    for(int v:adj[u]) if(v!=p){
        h[v]=h[u]+1;
        par[v]=u;
        pre(v,u);
        sz[u]+=sz[v];
    }
}

int idCh[N],head[N],curCh;
int tin[N],lst[N],tim;

void hld(int u, int p=-1){
    if(!head[curCh]){
        head[curCh]=u;
    }
    idCh[u]=curCh;
    tin[u]=++tim;
    lst[u]=tim;

    int bigCh=-1;
    for(int v:adj[u]) if(v!=p){
        if(bigCh==-1 || sz[bigCh]<sz[v]) bigCh=v;
    }

    if(bigCh!=-1) hld(bigCh,u);
    for(int v:adj[u]) if(v!=p && v!=bigCh){
        ++curCh;
        hld(v,u);
    }
}

int fw[N];
void upd(int id, int val){
    for(; id<=n; id+=id&-id) fw[id]+=val;
}
void updR(int l, int r, int val){
    upd(l,val); upd(r+1,-val);
}
int get(int id){
    int res=0;
    for(; id>0; id-=id&-id) res+=fw[id];
    return res;
}

/// phan chia ra hld -> de lay root hon

int cont[N],pass[N];
bool state[N],jump[N];

int getRoot(int u){
    while(true){
        if(jump[u]) u=par[u];
        else{
            int v=get(tin[u]);
            if(u==v) break;
            u=v;
        }
    }
    return u;
}

void connect(int u, int v){
    int rt=getRoot(u);
    cont[rt]=cont[rt]+cont[v]-pass[v];

    if(idCh[u]!=idCh[v]) jump[v]=1;
    else{
        rt=get(tin[u]);
        updR(tin[v],lst[v],rt-v);
        lst[rt]=lst[v];
    }
}

void disconnect(int u, int v){
    int rt=getRoot(u);
    pass[v]=cont[v]=cont[rt];

    if(idCh[u]!=idCh[v]) jump[v]=0;
    else{
        rt=get(tin[u]);
        updR(tin[v],lst[rt],v-rt);
        lst[v]=lst[rt]; lst[rt]=tin[u];
    }
}

void solve(){
    cin>>n>>m>>q;
    foru(i,1,n-1){
        int u,v;cin>>u>>v;
        edge[i]={u,v};
        adj[u].eb(v);adj[v].eb(u);
    }

    pre(1);
    hld(1);

    foru(i,1,n-1){
        if(tin[edge[i].fi]>tin[edge[i].se]) swap(edge[i].fi, edge[i].se);
    }
    foru(i,1,n) cont[i]=1;
    foru(i,1,n) updR(tin[i],tin[i],i);

    foru(_,1,m){
        int d; cin>>d;
        int u=edge[d].fi, v=edge[d].se;
        if(!state[d]){
            connect(u,v);
        } else{
            disconnect(u,v);
        }
        state[d]^=1;
    }

    foru(_,1,q){
        int c; cin>>c;
        cout<<cont[getRoot(c)]<<'\n';
    }
}

int32_t main(){
    #define task "test"
    if(fopen(task".inp","r")){
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
    cin.tie(0)->sync_with_stdio(0);

    solve();
}

Compilation message (stderr)

synchronization.cpp: In function 'int32_t main()':
synchronization.cpp:152:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  152 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
synchronization.cpp:153:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  153 |         freopen(task".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 10 / 10
• Subtask 4: 20 / 20
• Subtask 5: 40 / 40