Submission #950843

#	Time	Username	Problem	Language	Result	Execution time	Memory
950843		Ahmed57	Synchronization (JOI13_synchronization)	C++17	100 / 100	334 ms	25032 KiB

synchronization

#include "bits/stdc++.h"

using namespace std;
int in[100001],outt[100001];
int P[100001][20];
int bit[100001],dep[100001],ans[100001];
int n;vector<int> adj[100001];
int timer =0 ;
void add(int x,int v){
    while(x<=n){
        bit[x]+=v;
        x+=x&-x;
    }
}
int sum(int x){
    int ret = 0;
    while(x>=1){
        ret+=bit[x];
        x-=x&-x;
    }
    return ret;
}
void dfs(int x,int pr){
    in[x] = ++timer;
    P[x][0] = pr;
    dep[x] = dep[pr]+1;
    for(int j = 1;j<20;j++){
        P[x][j] = P[P[x][j-1]][j-1];
    }
    for(auto j:adj[x]){
        if(j==pr)continue;
        dfs(j,x);
    }
    outt[x] = timer;
}
int find(int x){
    int no = sum(in[x]);
    for(int j = 19;j>=0;j--){
        if(P[x][j]==0)continue;
        if(sum(in[P[x][j]])==no){
            x = P[x][j];
        }
    }
    return x;
}
void se(int x){
    add(in[x],1);
    add(outt[x]+1,-1);
}
void re(int x){
    add(in[x],-1);
    add(outt[x]+1,1);
}
signed main() {
    ios_base::sync_with_stdio(false);cin.tie(0);
    int m,q;cin>>n>>m>>q;
    int vis[n] = {0};
    int lol[n] = {0};
    vector<pair<int,int>> ed;

    for(int i = 0;i<n-1;i++){
        int a,b;cin>>a>>b;
        adj[a].push_back(b);
        adj[b].push_back(a);
        ed.push_back({a,b});
        vis[i] = 0;
    }
    dfs(1,0);
    for(int i = 0;i<n-1;i++){
        if(dep[ed[i].first]<dep[ed[i].second])swap(ed[i].first,ed[i].second);
    }
    for(int i = 1;i<=n;i++){
        ans[i] = 1;
        add(in[i],1);
        add(outt[i]+1,-1);
    }
    for(int i = 0;i<m;i++){
        int x;cin>>x;x--;
        if(vis[x]==0){
            int cost = -lol[x]+ans[find(ed[x].second)]+ans[ed[x].first];
            re(ed[x].first);
            ans[find(ed[x].second)] = cost;
        }else{
            lol[x] = ans[find(ed[x].second)];
            ans[ed[x].first] = lol[x];
            se(ed[x].first);
        }
        vis[x] = !vis[x];
    }
    for(int i = 0;i<q;i++){
        int x;cin>>x;
        cout<<ans[find(x)]<<endl;
    }
}

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