class Solution {
public:
    long long countSubarrays(vector<int>& a, long long k) {
         long long ans=0;
         int n=a.size();
         vector<long long> prefix(n,0); prefix[0]=a[0];
         for(int i=1;i<n;i++) prefix[i]=prefix[i-1]+(long long)a[i];
         for(int i=0;i<n;i++)
         {
             int l=0,r=i,temp=n+1;
             //first l where score[l,r]*(r-l+1)<k
             while(l<=r)
             {
                 int mid=(l+r)/2;
                 long long sum=prefix[i];
                 if(mid!=0) sum-=prefix[mid-1];
                 long long score=(sum*(long long)(i-mid+1));

                 if(score>=k){
                     l=mid+1; continue;
                 }
                 else{
                     temp=min(temp,mid);
                     r=mid-1; continue;
                 }
             }
             if(temp!=(n+1)) ans+=(i-temp+1);
         }
        return ans;
    }
};