Submission #1212292

#	Time	Username	Problem	Language	Result	Execution time	Memory
1212292		minhpk	Synchronization (JOI13_synchronization)	C++20	100 / 100	627 ms	63024 KiB

synchronization

#include <bits/stdc++.h>
#define int long long
using namespace std;
int a,b,c;
vector <int> z[1000005];
int sta[1000005];
int fin[1000005];
int rev[1000005];
int tour;
int sz[1000005];
int same[1000005];
int active[1000005];

int par[100005][25];
int f[4000005];
int lazy[4000005];
int high[1000005];
pair<int,int> edge[1000005];

void push(int id){
    if (lazy[id]!=0){
        lazy[id*2]+=lazy[id];
        lazy[id*2+1]+=lazy[id];

        f[id*2]+=lazy[id];
        f[id*2+1]+=lazy[id];

        lazy[id]=0;
    }
}

void dfs(int i,int parent){
    tour++;
    sta[i]=tour;
    rev[tour]=i;
    par[i][0]=parent;
    for (auto p:z[i]){
         if (p==parent){
             continue;
         }
         high[p]=high[i]+1;
         dfs(p,i);
    }

    fin[i]=tour;
}

void build(int id,int l,int r){
    if (l==r){
        f[id]=high[rev[l]];
        return;
    }
    int mid=(l+r)/2;
    build(id*2,l,mid);
    build(id*2+1,mid+1,r);
}

void update(int id,int l,int r,int x,int y,int val){
     if (x>r || y<l){
         return;
     }
     if (l>=x && y>=r){
         f[id]+=val;
         lazy[id]+=val;
         return;
     }
     int mid=(l+r)/2;
     push(id);
     update(id*2,l,mid,x,y,val);
     update(id*2+1,mid+1,r,x,y,val);
}

int get(int id,int l,int r,int pos){
    if (l==r){
        return f[id];
    }
    int mid=(l+r)/2;
    push(id);
    if (pos<=mid){
        return get(id*2,l,mid,pos);
    }else{
        return get(id*2+1,mid+1,r,pos);
    }
}

int ancestor(int x){
   int val=get(1,1,tour,sta[x]);
   for (int i=20;i>=0;i--){
        int nxt=par[x][i];
        if (nxt!=0 && get(1,1,tour,sta[nxt])==val){
            x=par[x][i];
        }
   }
   return x;
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> a >> b >> c;
    for (int i=1;i<a;i++){
         int x,y;
         cin >> x >> y;
         z[x].push_back(y);
         z[y].push_back(x);
         edge[i]={x,y};
    }
    tour=0;
    high[1]=0;

    dfs(1,0);
    par[0][0]=0;
    for (int j=1;j<=20;j++){
         for (int i=0;i<=a;i++){
             par[i][j]=par[par[i][j-1]][j-1];
         }
    }
    for (int i=1;i<=a;i++){
         sz[i]=1;
         same[i]=0;
         active[i]=0;
    }
    build(1,1,tour);
    int q=1;
    while (b--){
         int t;
         cin >> t;
         auto [x,y]=edge[t];
         if (par[y][0]==x){
             swap(x,y);
         }

         if (!active[t]){
             int anc=ancestor(y);
           //  cout << t << " " << anc << " ";
             sz[anc]+=sz[x]-same[x];
             update(1,1,tour,sta[x],fin[x],-1);
           //  cout << sz[anc] << "\n";
         }else{
             int anc=ancestor(y);
             sz[x]=sz[anc];
             same[x]=sz[anc];
             update(1,1,tour,sta[x],fin[x],1);
         }
         active[t]=1-active[t];
         q++;
    }


    while (c--){
        int x;
        cin >> x;

        int anc=ancestor(x);
        cout <<  sz[anc] << "\n";
    }
    return 0;
}

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