Submission #68194436

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Source Code Expand

#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long int ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<vvvl> vvvvl;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;
typedef vector<vvvb> vvvvb;
typedef pair<ll,ll> pl;
typedef pair<ll,pl> ppl;
typedef pair<ll,ppl> pppl;
typedef pair<ll,pppl> pppppl;
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(a) begin(a),end(a)
#define sz(a) (int)(a).size()
#define F first
#define S second
#define bs(A,x) binary_search(all(A),x)
#define lb(A,x) (ll)(lower_bound(all(A),x)-A.begin())
#define ub(A,x) (ll)(upper_bound(all(A),x)-A.begin())
#define cou(A,x) (ll)(upper_bound(all(A),x)-lower_bound(all(A),x))
template<typename T>using min_priority_queue=priority_queue<T,vector<T>,greater<T>>;
template<class T>bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T&a,T b){if(b<a){a=b;return 1;}return 0;}
//*
using mint=modint998244353;
const ll mod=998244353;
//*/
/*
using mint=modint1000000007;
const ll mod=1000000007;
//*/
//using mint=modint;
//*
typedef vector<mint> vm;
typedef vector<vm> vvm;
typedef vector<vvm> vvvm;
typedef vector<vvvm> vvvvm;
ostream&operator<<(ostream&os,mint a){os<<a.val();return os;}
istream&operator>>(istream&is,mint&a){int x;is>>x;a=mint(x);return is;}
//*/
template<typename T1,typename T2>ostream&operator<<(ostream&os,pair<T1,T2>p){os<<p.F<<" "<<p.S;return os;}
template<typename T1,typename T2>istream&operator>>(istream&is,pair<T1,T2>&p){is>>p.F>>p.S;return is;}
template<typename T>ostream&operator<<(ostream&os,vector<T>v){rep(i,0,sz(v))os<<v[i]<<(i+1!=sz(v)?" ":"");return os;}
template<typename T>istream&operator>>(istream&is,vector<T>&v){for(T&in:v)is>>in;return is;}
int main(){
  cin.tie(0)->sync_with_stdio(0);
  cin.exceptions(cin.failbit);
  ll N;cin>>N;
  vl A(N);cin>>A;
  ll Q;cin>>Q;
  set<ll>S;
  rep(i,0,N-1)if(A[i]+A[i+1]==0)S.insert(i);
  fenwick_tree<ll>F(N);
  rep(i,0,N)F.add(i,A[i]);
  ll ans=0;
  if(sz(S)>1)for(auto it=S.begin();it!=prev(S.end());it++){
    ll l=*it,r=*next(it);
    ans+=min(3ll,r-l);
  }
  for(auto x:S)if(S.count(x+1))ans--;
  //(0,0,...,0)の処理をミスっている...
  while(Q--){
    ll i;cin>>i;i--;
    if(i&&A[i-1]+A[i]==0){
      S.erase(i-1);
      if(S.count(i-2))ans++;
      if(S.count(i))ans++;
      auto it=S.lower_bound(i-1);
      if(it!=S.end())ans-=min(3ll,*it-i+1);
      if(it!=S.begin())ans-=min(3ll,i-1-*prev(it));
      if(it!=S.begin()&&it!=S.end())ans+=min(3ll,*it-*prev(it));
    }
    if(i+1<N&&A[i]+A[i+1]==0){
      S.erase(i);
      if(S.count(i-1))ans++;
      if(S.count(i+1))ans++;
      auto it=S.lower_bound(i);
      if(it!=S.end())ans-=min(3ll,*it-i);
      if(it!=S.begin())ans-=min(3ll,i-*prev(it));
      if(it!=S.begin()&&it!=S.end())ans+=min(3ll,*it-*prev(it));
    }
    F.add(i,-A[i]);
    A[i]=!A[i];
    F.add(i,A[i]);
    if(i&&A[i-1]+A[i]==0){
      auto it=S.lower_bound(i-1);
      if(it!=S.end())ans+=min(3ll,*it-i+1);
      if(it!=S.begin())ans+=min(3ll,i-1-*prev(it));
      if(it!=S.begin()&&it!=S.end())ans-=min(3ll,*it-*prev(it));
      S.insert(i-1);
      if(S.count(i-2))ans--;
      if(S.count(i))ans--;
    }
    if(i+1<N&&A[i]+A[i+1]==0){
      auto it=S.lower_bound(i);
      if(it!=S.end())ans+=min(3ll,*it-i);
      if(it!=S.begin())ans+=min(3ll,i-*prev(it));
      if(it!=S.begin()&&it!=S.end())ans-=min(3ll,*it-*prev(it));
      S.insert(i);
      if(S.count(i-1))ans--;
      if(S.count(i+1))ans--;
    }
    ll d;
    if(S.empty()){
      if(A[0]+A[N-1]==0)d=3;
      else if(A[0]+A[N-1]==1)d=2;
      else if(F.sum(0,N)==N)d=N;
      else d=2;
    }
    else{
      ll l=*S.begin(),r=*prev(S.end());
      if(l+1<3)d=l+1;
      else if(A[0]+A[l]==0)d=3;
      else if(A[0]+A[l]==1)d=2;
      else if(F.sum(0,l)==l)d=l+1;
      else d=2;
      if(N-r-1<3)d+=N-1-r;
      else if(A[N-1]+A[r+1]==0)d+=3;
      else if(A[N-1]+A[r+1]==1)d+=2;
      else if(F.sum(r+1,N)==N-r-1)d+=N-r-1;
      else d+=2;
    }
    cout<<ans+d<<endl;
  }
  return 0;
}

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