Submission #902223

#	Time	Username	Problem	Language	Result	Execution time	Memory
902223		089487	Joker (BOI20_joker)	C++14	100 / 100	567 ms	21556 KiB

Joker

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("sse4,abm,avx,popcnt")
#include<bits/stdc++.h>
//#define int long long
#define quick ios::sync_with_stdio(0);cin.tie(0);
#define rep(x,a,b) for(int x=a;x<=b;x++)
#define repd(x,a,b) for(int x=a;x>=b;x--)
#define lowbit(x) (x&-x)
#define F first
#define S second
#define sz(x) (int)(x.size())
#define all(x) x.begin(),x.end()
#define mp make_pair
#define eb emplace_back
using namespace std;
typedef pair<int,int> pii;
void debug(){
    cout<<"\n";
}
template <class T,class ... U >
void debug(T a, U ... b){
    cout<<a<<" ",debug(b...);
}
const int N=5e5+2;
pii e[N];
int p[N];
int sz[N];
void init(int n){
    rep(i,1,n) p[i]=i,sz[i]=1;
}
int fp(int x){
    for(;x!=p[x];x=p[x]) ;
    return p[x];
}
int ans[N];
stack<tuple<int,int,int>> state;
int n,m;
void _Union(int a,int b){
    a=fp(a);
    b=fp(b);
    if(a==b) {
        state.push(make_tuple(-1,-1,-1));
        return ;
    }
    //assert(a!=b);
    if(sz[a]<sz[b]) swap(a,b);
    state.push(make_tuple(a,sz[a],b));
    p[b]=a;
    sz[a]+=sz[b];
    return ;
}
bool Union(int a,int b){
    int fa=fp(a);
    int fb=fp(b);
    if(fa==fb) return false;
    _Union(fa,b+n);
    _Union(fb,a+n);
    return true;
}
void undo(){
    auto [a,sza,b]=state.top();
    state.pop();
    if(a==-1) return ;
    sz[a]=sza;
    p[b]=b;
}
void solve(int l,int r,int vl,int vr){
    if(l>r||vl>vr) return ;
    //debug("solve",l,r,vl,vr);
    if(vl==vr){
        rep(i,l,r) ans[i]=vl;
        return ;
    }
    int mid=(l+r)>>1;
    ans[mid]=vr;
    for(int i=mid;i<=vr;i++){
        if(i==r+1) i=max(i,vl);
        if(!Union(e[i].F,e[i].S)){
            ans[mid]=i-1;
            break;
        }
    }
    assert(ans[mid]>=vl&&ans[mid]<=vr);
    // [r+1,vl-1] is done
    for(int i=ans[mid];i>=max(vl,mid);i--){
        undo();
        undo();
    }
    solve(l,mid-1,vl,ans[mid]);
    rep(i,mid,min(r,vl-1)){
        undo();
        undo();
    }
    rep(i,max(r+1,vl),ans[mid]-1) Union(e[i].F,e[i].S);
    solve(mid+1,r,ans[mid],vr);
    rep(i,max(r+1,vl),ans[mid]-1) undo(),undo();
}
signed main(){
	quick
    int q;
    cin>>n>>m>>q;
    init(n*2);
    rep(i,0,m-1){
        cin>>e[i].F>>e[i].S;
        e[i+m]=e[i];
    }
    solve(0,m,0,m*2-1);
    /*rep(i,0,m-1){
        cout<<ans[i]<<" \n"[i==m-1];
    }
    rep(i,0,m-1){
        init(2*n);
        ans[i]=-1;
        rep(j,i,m-1){
            if(Union(e[j].F,e[j].S)) ans[i]=j;
            else break;
        }
        cout<<ans[i]<<" \n"[i==m-1];
    }*/
    string Ans[2]={"YES","NO"};
    while(q--){
        int l,r;
        cin>>l>>r;
        --l,--r;
        cout<<Ans[(ans[r+1]>=l+m-1)]<<"\n";
    }
}

Compilation message (stderr)

Joker.cpp: In function 'void undo()':
Joker.cpp:61:10: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   61 |     auto [a,sza,b]=state.top();
      |          ^

• Subtask 1: 6 / 6
• Subtask 2: 8 / 8
• Subtask 3: 25 / 25
• Subtask 4: 10 / 10
• Subtask 5: 22 / 22
• Subtask 6: 29 / 29