Submission #3695355

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Source Code Expand

#include <bits/stdc++.h>
#define rep(i, a, b) for(int i = int(a); i < int(b); i++)
#define rer(i, a, b) for(int i = int(a) - 1; i >= int(b); i--)

using namespace std;
typedef long long int ll;
const ll MAX_H=1e8;
ll bit[MAX_H+1], n;
ll a[100000];
ll sum(ll i){
    ll s=0;
    while(i>0){
        s+=bit[i];
        i-=i&-i;
    }
    return s;
}

void add(ll i, ll x){
    while(i<=n){
        bit[i]+=x;
        i+=i&-i;
    }
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n;
    rep(i,0,n) cin>>a[i];
    set<ll> s;
    rep(i,0,n) s.insert(a[i]);
    if(s.size()!=n){
        cout <<-1<<"\n";
        return 0;
    }
    ll ans=0;
    rep(j,0,n){
        ans+=(j-sum(a[j]))*a[j];
        add(a[j],1);
    }
    cout << ans<<"\n";
}

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