Submission #231409

#	Time	Username	Problem	Language	Result	Execution time	Memory
231409		thebes	Synchronization (JOI13_synchronization)	C++14	100 / 100	910 ms	28024 KiB

synchronization

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

const int MN = 1e5+5, LG = 19;
int st[3*MN], lz[3*MN], sp[MN][LG], N, M, Q, i, x, y, dep[MN], vis[MN][2], lst[MN], nxt, sz[MN], on[MN];
pair<int,int> e[MN];
vector<int> adj[MN];

inline void upd_lz(int i,int s,int e){
    st[i] += lz[i];
    if(s!=e){
        lz[2*i] += lz[i];
        lz[2*i+1] += lz[i];
    }
    lz[i] = 0;
}

void upd(int i,int s,int e,int ss,int se,int v){
    upd_lz(i, s, e);
    if(s>=ss&&e<=se){lz[i]=v; upd_lz(i,s,e);}
    else{
        if((s+e)/2<ss) upd(2*i+1,(s+e)/2+1,e,ss,se,v),upd_lz(2*i,s,(s+e)/2);
        else if((s+e)/2>=se) upd(2*i,s,(s+e)/2,ss,se,v),upd_lz(2*i+1,(s+e)/2+1,e);
        else upd(2*i,s,(s+e)/2,ss,se,v),upd(2*i+1,(s+e)/2+1,e,ss,se,v);
        st[i]=st[2*i]+st[2*i+1];
    }
}

int qu(int i,int s,int e,int idx){
    upd_lz(i,s,e);
    if(s==e) return st[i];
    else if((s+e)/2<idx) return qu(2*i+1,(s+e)/2+1,e,idx);
    else return qu(2*i,s,(s+e)/2,idx);
}

void dfs(int n,int p,int d){
    vis[n][0] = ++nxt;
    sp[n][0]=p; dep[n]=d;
    for(auto v : adj[n]){
        if(v==p) continue;
        dfs(v,n,d+1);
    }
    vis[n][1] = nxt;
}

int anc(int n){
    int val = qu(1,1,N,vis[n][0]);
    for(int i=LG-1;i>=0;i--){
        if(sp[n][i]){
            int nn = sp[n][i];
            if(qu(1,1,N,vis[nn][0])==val)
                n = nn;
        }
    }
    return n;
}

int main(){
    for(scanf("%d%d%d",&N,&M,&Q),i=1;i<N;i++){
        scanf("%d%d",&x,&y);
        adj[x].push_back(y);
        adj[y].push_back(x);
        e[i]={x,y};
    }
    dfs(1,0,1);
    for(int j=1;j<LG;j++){
        for(i=1;i<=N;i++)
            sp[i][j]=sp[sp[i][j-1]][j-1];
    }
    for(i=1;i<N;i++){
        if(dep[e[i].first]>dep[e[i].second])
            swap(e[i].first,e[i].second);
    }
    for(i=2;i<=N;i++) upd(1,1,N,vis[i][0],vis[i][1],1);
    for(i=1;i<=N;i++) sz[i]=1;
    for(i=1;i<=M;i++){
        scanf("%d",&x);
        int p=e[x].first, c=e[x].second;
        if(on[x]){
            int rt = anc(c);
            lst[x] = sz[c] = sz[rt];
            upd(1,1,N,vis[c][0],vis[c][1],1);
        }
        else{
            upd(1,1,N,vis[c][0],vis[c][1],-1);
            int rt = anc(c);
            sz[rt] += sz[c]-lst[x];
        }
        on[x]=!on[x];
    }
    for(i=1;i<=Q;i++){
        scanf("%d",&x);
        printf("%d\n",sz[anc(x)]);
    }
    return 0;
}

Compilation message (stderr)

synchronization.cpp: In function 'int main()':
synchronization.cpp:78:13: warning: unused variable 'p' [-Wunused-variable]
         int p=e[x].first, c=e[x].second;
             ^
synchronization.cpp:59:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(scanf("%d%d%d",&N,&M,&Q),i=1;i<N;i++){
         ~~~~~~~~~~~~~~~~~~~~~~~~^~~~
synchronization.cpp:60:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&x,&y);
         ~~~~~^~~~~~~~~~~~~~
synchronization.cpp:77:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&x);
         ~~~~~^~~~~~~~~
synchronization.cpp:92:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d",&x);
         ~~~~~^~~~~~~~~

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