Submission #1214803

#	Time	Username	Problem	Language	Result	Execution time	Memory
1214803		biank	Diversity (CEOI21_diversity)	C++20	100 / 100	667 ms	3744 KiB

diversity

#include <bits/stdc++.h>

using namespace std;

#define forn(i,n) for(int i=0;i<int(n);i++)
#define forsn(i,s,n) for(int i=int(s);i<int(n);i++)
#define dforn(i,n) for(int i=int(n)-1;i>=0;i--)
#define dforsn(i,s,n) for(int i=int(n)-1;i>=int(s);i--)
#define fst first
#define snd second
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()

typedef long long ll;
typedef vector<ll> vll;
typedef vector<int> vi;
typedef pair<int,int> ii;

const int B=550;
const int MAX_A=3e5+9;

ll solve(vector<ii> &g, int n){
    int l=0;
    ll ret=0LL;
    for(const auto&[x,c]:g){
        ret+=(n+1LL)*c*n;
        ret-=(l+1LL)*c*l;
        ret-=(2LL*l+1LL)*x*c*(c-1LL)/2LL;
        ret-=(c-1LL)*c*(2LL*c-1LL)/6LL*x*x;
        ret-=(n-l+1LL)*(n-l)*c;
        ret+=(2LL*n-2LL*l+1LL)*x*c*(c+1LL)/2LL;
        ret-=(c+1LL)*c*(2LL*c+1LL)/6LL*x*x;
        l+=x*c;
    }
    return ret/2;
}

struct Query{
    int l,r,id;
    bool operator<(const Query &o){
        if(l/B!=o.l/B) return l<o.l;
        if(l/B&1) return r>o.r;
        return r<o.r;
    }
};

int tot[MAX_A],cnt[MAX_A],freq[MAX_A];
bool vis[MAX_A];

void add(int x, int d){
    freq[cnt[x]]--;
    cnt[x]+=d;
    freq[cnt[x]]++;
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    
    int n,q;
    cin>>n>>q;
    vi a(n);
    forn(i,n){
        cin>>a[i];
        tot[a[i]]++;
    }
    vi lol;
    forn(x,MAX_A){
        if(tot[x]>=B) lol.pb(x);
    }
    vector<Query> v(q);
    forn(i,q){
        int l,r;
        cin>>l>>r;
        --l,--r;
        v[i]={l,r,i};
    }
    
    sort(all(v));
    vll ret(q);
    int curr_l=0,curr_r=-1;
    for(auto[l,r,id]:v){
        while(curr_l<l) add(a[curr_l++],-1);
        while(curr_r>r) add(a[curr_r--],-1);
        while(curr_l>l) add(a[--curr_l],1);
        while(curr_r<r) add(a[++curr_r],1);
        vector<ii> vec[2];
        bool flag=true;
        vi active;
        forsn(i,1,B) if(freq[i]) active.pb(i);
        for(int x:lol){
            if(!vis[cnt[x]]&&cnt[x]>=B){
                active.pb(cnt[x]);
                vis[cnt[x]]=true;
            }
        }
        sort(all(active),greater<int>());
        for(int x:active){
            int c=freq[x];
            vec[flag].eb(x,c-c/2);
            vec[!flag].eb(x,c/2);
            flag^=c%2==1;
        }
        for(int x:lol) vis[cnt[x]]=false;
        reverse(all(vec[0]));
        vec[0].insert(end(vec[0]),all(vec[1]));
        ret[id]=solve(vec[0],r-l+1);
    }
    forn(i,q) cout<<ret[i]<<'\n';
    
    return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 10 / 10
• Subtask 3: 8 / 8
• Subtask 4: 16 / 16
• Subtask 5: 26 / 26
• Subtask 6: 36 / 36