Given an array of integers arr and two integers k and threshold, return the number of sub-arrays of sizekand average greater than or equal tothreshold.
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:
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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.
To efficiently count subarrays of size k with average at least threshold, we can use a sliding window of size k and keep track of the sum. If the sum of the window is at least k * threshold, the average is sufficient.
classSolution {
public:int numOfSubarrays(vector<int>& arr, int k, int threshold) {
int ans =0, sum =0;
for (int i =0; i < arr.size(); ++i) {
sum += arr[i];
if (i >= k) sum -= arr[i - k];
if (i >= k -1&& sum >= k * threshold) ans++;
}
return ans;
}
};
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funcnumOfSubarrays(arr []int, kint, thresholdint) int {
ans, sum:=0, 0fori:=0; i < len(arr); i++ {
sum+=arr[i]
ifi>=k {
sum-=arr[i-k]
}
ifi>=k-1&&sum>=k*threshold {
ans++ }
}
returnans}
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classSolution {
publicintnumOfSubarrays(int[] arr, int k, int threshold) {
int ans = 0, sum = 0;
for (int i = 0; i < arr.length; i++) {
sum += arr[i];
if (i >= k) sum -= arr[i - k];
if (i >= k - 1 && sum >= k * threshold) ans++;
}
return ans;
}
}
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classSolution {
funnumOfSubarrays(arr: IntArray, k: Int, threshold: Int): Int {
var ans = 0var sum = 0for (i in arr.indices) {
sum += arr[i]
if (i >= k) sum -= arr[i - k]
if (i >= k - 1&& sum >= k * threshold) ans++ }
return ans
}
}
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classSolution:
defnumOfSubarrays(self, arr: list[int], k: int, threshold: int) -> int:
ans =0 s = sum(arr[:k])
if s >= k * threshold:
ans +=1for i in range(k, len(arr)):
s += arr[i] - arr[i - k]
if s >= k * threshold:
ans +=1return ans
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impl Solution {
pubfnnum_of_subarrays(arr: Vec<i32>, k: i32, threshold: i32) -> i32 {
let (mut ans, mut sum) = (0, 0);
let k = k asusize;
for i in0..arr.len() {
sum += arr[i];
if i >= k { sum -= arr[i - k]; }
if i +1>= k && sum >= (k asi32) * threshold { ans +=1; }
}
ans
}
}
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classSolution {
numOfSubarrays(arr: number[], k: number, threshold: number):number {
letans=0, sum=0;
for (leti=0; i<arr.length; i++) {
sum+=arr[i];
if (i>=k) sum-=arr[i-k];
if (i>=k-1&&sum>=k*threshold) ans++;
}
returnans;
}
}