Submission #846880

#	Time	Username	Problem	Language	Result	Execution time	Memory
846880		Ahmed57	Inside information (BOI21_servers)	C++17	50 / 100	466 ms	130580 KiB

servers

#include <bits/stdc++.h>
using namespace std;
int NODES=0;
bool seg[40000000];int L[40000000],R[40000000],n;
void update(int p, int q, int l, int r, int x)
{
    if(l==r){seg[p]=1;return;}
    int md = (l+r)/2;
    seg[p]=1;
    if(x<=md)R[p]=R[q],L[p]=++NODES,update(L[p],L[q],l,md,x);
    else L[p]=L[q],R[p]=++NODES,update(R[p],R[q],md+1,r,x);
}
bool query(int p,int l,int r,int x){
    if(l==r){
        return seg[p];
    }
    int md=(l+r)/2;
    if(x<=md)return query(L[p],l,md,x);
    else return query(R[p],md+1,r,x);
}
vector<int> v;
void iterate(int p,int l,int r){
    if(!seg[p])return;
    if(l==r)v.push_back(l);
    else{
        int md=(l+r)/2;
        iterate(L[p],l,md);
        iterate(R[p],md+1,r);
    }
}
int pr[125001];
int gs[125001];
void merg(int a,int b){
    if(gs[a]>gs[b])swap(a,b);
    iterate(pr[a],1,n);int tm;
    for(auto x:v){
        tm = ++NODES;
        update(tm,pr[b],1,n,x);
        pr[b]=tm;
    }
    pr[a]=tm,pr[b]=tm,gs[b]+=gs[a],gs[a]=gs[b];
    v.clear();
}
int main(){
    int q; cin>>n>>q;
    for(int i = 1;i<=n;i++){
        pr[i] = ++NODES , gs[i] = 1;
    }
    for(int i = 1;i<=n;i++){
        int tm = ++NODES;
        update(tm,pr[i],1,n,i);
        pr[i]=tm;
    }
    q+=n-1;
    while(q--){
        char c;cin>>c;
        if(c=='S'){int a,b;cin>>a>>b;merg(a,b);}
        else{
            int a,b;cin>>a>>b;
            cout<<(query(pr[a],1,n,b)?"yes\n":"no\n");
        }
    }
}

Compilation message (stderr)

servers.cpp: In function 'void merg(int, int)':
servers.cpp:41:10: warning: 'tm' may be used uninitialized in this function [-Wmaybe-uninitialized]
   41 |     pr[a]=tm,pr[b]=tm,gs[b]+=gs[a],gs[a]=gs[b];
      |     ~~~~~^~~

• Subtask 1: 2.5 / 2.5
• Subtask 2: 0 / 2.5
• Subtask 3: 2.5 / 2.5
• Subtask 4: 0 / 2.5
• Subtask 5: 5 / 5
• Subtask 6: 0 / 5
• Subtask 7: 10 / 10
• Subtask 8: 0 / 10
• Subtask 9: 12.5 / 12.5
• Subtask 10: 0 / 12.5
• Subtask 11: 17.5 / 17.5
• Subtask 12: 0 / 17.5