Submission #1159949

#	Time	Username	Problem	Language	Result	Execution time	Memory
1159949		son2008	Synchronization (JOI13_synchronization)	C++20	100 / 100	194 ms	30020 KiB

synchronization

#include<bits/stdc++.h>
using namespace std;
#define task "task"
#define ii pair<int,int>
#define fi first
#define se second
//#define int long long
#define ll long long
#define ld double
#define mp make_pair
#define lg2 30
#define iii pair<ll,ii>
#define iiii pair<ii,ii>
#define base 29
#define eps 1e-8
int dx[]= {0LL,0LL,1,-1,1,1,-1,-1};
int dy[]= {1,-1,0LL,0LL,1,-1,1,-1};
const int maxn=2e5+5,maxm=1e4+5,maxq=1e5+5;
const int mod=1e9+7;
int n,m,q;
ii b[maxn];
int tin[maxn],tout[maxn],timer;
int h[maxn],P[maxn][lg2+1];
bool check[maxn];
int thua[maxn],ans[maxn];
vector<int>a[maxn];
struct FEN
{
    int n;
    vector<int>bit;
    FEN(){};
    FEN(int _n):bit(n+1,0),n(_n+1)
    {
    };
    int get(int r) {
        int ret = 0;
        for (; r >= 0; r = (r & (r + 1)) - 1)
            ret += bit[r];
        return ret;
    }

    int get(int l, int r) {
        return get(r) - get(l - 1);
    }

    void update(int idx, int delta) {
        for (; idx < n; idx = idx | (idx + 1))
            bit[idx] += delta;
    }

    void updateRange(int l,int r,int val)
    {
        update(l,val);
        update(r+1,-val);
    }
}bit;
void dfs(int u,int cha)
{
    ans[u]=1;
    tin[u]=++timer;
    for(int v:a[u])
    {
        if(v==cha)continue;
        h[v]=h[u]+1;
        P[v][0]=u;
        dfs(v,u);
    }
    tout[u]=timer;
}
void build_lca(){
        for(int j=1;j<=lg2;j++){
            for(int i=1;i<=n;i++)
                P[i][j]=P[P[i][j-1]][j-1];
}
}
int up(int u)
{
    for(int i=lg2;i>=0;i--)
    {
        if(P[u][i]&&bit.get(tin[u])-bit.get(tin[P[u][i]])==(1<<i)){
            u=P[u][i];
        }
    }
    return u;
}
void init()
{
    cin>>n>>m>>q;
    bit=FEN(n);
    for(int i=1;i<n;i++)
    {
        int u,v;
        cin>>u>>v;
        a[u].push_back(v);
        a[v].push_back(u);
        b[i]={u,v};
    }
}
void process()
{
    dfs(1,-1);
    build_lca();
    while(m--)
    {
        int id;cin>>id;
        int u=b[id].fi,v=b[id].se;
        if(h[u]>h[v])swap(u,v);
        if(!check[id])
        {
            ans[up(u)]+=ans[v]-thua[id];
            bit.updateRange(tin[v],tout[v],1);
        }
        else
        {
            ans[v]=thua[id]=ans[up(u)];
            bit.updateRange(tin[v],tout[v],-1);
        }
        check[id]^=1;
    }
    while(q--)
    {
        int x;
        cin>>x;
        cout<<ans[up(x)]<<'\n';
    }
}
signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if(fopen(task".inp","r"))
    {
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
    int t=1;
  //  cin>>t;
    while(t--)
    {
    init();
    process();
    }
    cerr <<endl<< "TIME : " << clock() * 0.001 << "s" << endl ;
}

Compilation message (stderr)

synchronization.cpp: In function 'int main()':
synchronization.cpp:134:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  134 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
synchronization.cpp:135:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  135 |         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