# 1343. Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold

## 1343. Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold

Given an array of integers `arr` and two integers `k` and `threshold`.

Return the number of sub-arrays of size `k` and average greater than or equal to `threshold`.

Example 1:

```Input: arr = [2,2,2,2,5,5,5,8], k = 3, threshold = 4
Output: 3
Explanation: Sub-arrays [2,5,5],[5,5,5] and [5,5,8] have averages 4, 5 and 6 respectively. All other sub-arrays of size 3 have averages less than 4 (the threshold).
```

Example 2:

```Input: arr = [1,1,1,1,1], k = 1, threshold = 0
Output: 5
```

Example 3:

```Input: arr = [11,13,17,23,29,31,7,5,2,3], k = 3, threshold = 5
Output: 6
Explanation: The first 6 sub-arrays of size 3 have averages greater than 5. Note that averages are not integers.
```

Example 4:

```Input: arr = [7,7,7,7,7,7,7], k = 7, threshold = 7
Output: 1
```

Example 5:

```Input: arr = [4,4,4,4], k = 4, threshold = 1
Output: 1
```

Constraints:

• `1 <= arr.length <= 10^5`
• `1 <= arr[i] <= 10^4`
• `1 <= k <= arr.length`
• `0 <= threshold <= 10^4`

### Solution

class Solution
{
public:
int numOfSubarrays(vector<int> &arr, int k, int threshold)
{
int st = 0, end = k - 1;
int curr = 0;
int cnt = k, ans = 0;
for (int i = st; i <= end; i++)
{
curr += arr[i];
}
if (curr / k >= threshold)
{
ans++;
}

while (end < arr.size())
{

end++;
if (end < arr.size())
{
curr += arr[end];
curr -= arr[st];
st++;

if ((curr / k) >= threshold)
{

ans++;
}
}
}
return ans;
}
};