Submission #285510

#	Time	Username	Problem	Language	Result	Execution time	Memory
285510		lukameladze	Mountains (NOI20_mountains)	C++14	0 / 100	233 ms	6392 KiB

Mountains

# include <bits/stdc++.h>
using namespace std;
long long tree[400005],j,n,ans,x,y,id,fix[100005],raod;
pair <long long , long long > a[100005];
void inc(int idx, int val)
{
    for (int i=idx; i<=n; i+=i&(-i))
    {
        tree[i]+=val;
    }
}
long long getans (int idx)
{
    long  long pas=0;
    for (int i=idx; i>0; i-=i&(-i))
    {
        pas+=tree[i];
    }
    return pas;
}
int main()
{
    cin>>n;
    for (int i=1; i<=n; i++)
    {
        cin>>a[i].first;
        a[i].second=i;
    }
    sort(a+1,a+n+1);
    for (int i=1; i<=n; i++)
    {
        if(a[i].first!=a[i-1].first) 
        fix[a[i].second]=1;//cout<<i<<" ";
    }
   // cout<<endl;
    inc(a[1].second,1);
    for (int i=2; i<=n; i++)
    {
        if (fix[a[i].second]==1) 
        { j=i; break;}
        inc(a[i].second,1);
    }
    for (int i=j; i<=n; i++)
    {
        raod++;
        id=a[i].second;
        x=getans(id-1);
        y=getans(n)-getans(id);
       // cout<<id<<" "<<x<<" "<<y<<" "<<x*y<<endl;
        ans+=x*y;
        if (fix[a[i+1].second]==1)
        {
        inc(a[i].second,raod);
        raod=0;
        }
    }
    cout<<ans<<endl;
}

• Subtask 1: 0 / 2
• Subtask 2: 0 / 4
• Subtask 3: 0 / 9
• Subtask 4: 0 / 36
• Subtask 5: 0 / 28
• Subtask 6: 0 / 9
• Subtask 7: 0 / 12