1343. Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold
Difficulty: Medium
Related Topics: Array
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
Language: Python3
class Solution:
def numOfSubarrays(self, arr: List[int], k: int, threshold: int) -> int:
rep=0
target=k*threshold
cur=sum(arr[:k])
if cur>=target:
rep+=1
l,r=0,k
while r<len(arr):
cur-=arr[l]
cur+=arr[r]
l+=1
r+=1
if cur>=target:
rep+=1
return rep