Submission #987134

#	Time	Username	Problem	Language	Result	Execution time	Memory
987134		guagua0407	Synchronization (JOI13_synchronization)	C++17	100 / 100	464 ms	30984 KiB

synchronization

//#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define f first
#define s second
#define all(x) x.begin(),x.end()
#define _ ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

const int mxn=1e5+5;
vector<int> adj[mxn];
vector<int> dp[mxn];
int up[mxn][20];
int st[mxn],en[mxn];
bool ok[mxn];
int depth[mxn];
int bit[mxn];
int cnt[mxn];
int timer=0;

void update(int pos,int val){
    for(;pos<mxn;pos+=(pos&-pos)){
        bit[pos]+=val;
    }
}

int query(int pos){
    int ans=0;
    for(;pos>0;pos-=(pos&-pos)){
        ans+=bit[pos];
    }
    return ans;
}

void dfs(int v,int p=0){
    up[v][0]=p;
    st[v]=++timer;
    depth[v]=depth[p]+1;
    dp[v].push_back(v);
    cnt[v]=1;
    for(auto u:adj[v]){
        if(u==p) continue;
        dfs(u,v);
    }
    en[v]=timer;
}

int go(int v,int len){
    for(int i=0;i<20;i++){
        if(len&(1<<i)) v=up[v][i];
    }
    return v;
}

int get(int b){
    int ans=0;
    for(int i=19;i>=0;i--){
        int tmp=ans+(1<<i);
        int v=go(b,tmp);
        int val=query(st[b])-query(st[v]);
        if(val>=tmp){
            ans=tmp;
        }
    }
    return go(b,ans);
}

int main() {_
    int n,m,q;
    cin>>n>>m>>q;
    vector<pair<int,int>> e(n-1);
    for(int i=0;i<n-1;i++){
        int a,b;
        cin>>a>>b;
        e[i]={a,b};
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    vector<int> qs;
    for(int i=0;i<m;i++){
        int x;
        cin>>x;
        x--;
        qs.push_back(x);
    }
    int root=1;
    dfs(root);
    for(int j=1;j<20;j++){
        for(int i=1;i<=n;i++){
            up[i][j]=up[up[i][j-1]][j-1];
        }
    }
    for(auto x:qs){
        int a=e[x].f;
        int b=e[x].s;
        if(depth[a]>depth[b]) swap(a,b);
        if(ok[x]){
            int v=get(a);
            cnt[b]=cnt[v];
            ok[x]=false;
            update(st[b],-1);
            update(en[b]+1,1);
            continue;
        }
        ok[x]=true;
        update(st[b],1);
        update(en[b]+1,-1);
        int v=get(b);
        assert(v!=0);
        cnt[v]+=(int)dp[b].size();
        if(dp[v].size()<dp[b].size()) swap(dp[v],dp[b]);
        dp[v].insert(dp[v].end(),all(dp[b]));
        dp[b].clear();
    }
    for(int i=1;i<=n;i++){
        cnt[i]=cnt[get(i)];
    }
    for(int i=0;i<q;i++){
        int x;
        cin>>x;
        cout<<cnt[x]<<'\n';
    }
    return 0;
}
//maybe its multiset not set
//yeeorz
//laborz

Compilation message (stderr)

synchronization.cpp: In function 'void setIO(std::string)':
synchronization.cpp:15:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
synchronization.cpp:16:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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