Create 1343-number-of-sub-arrays-of-size-k-and-average-greater-than-or-equal-to-threshold.js

Author: everthis

1343-number-of-sub-arrays-of-size-k-and-average-greater-than-or-equal-to-threshold.js

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+/**
+ * @param {number[]} arr
+ * @param {number} k
+ * @param {number} threshold
+ * @return {number}
+ */
+const numOfSubarrays = function(arr, k, threshold) {
+  const n = arr.length
+  const pre = Array(n).fill(0)
+  pre[0] = arr[0]
+  for(let i = 1; i < n; i++) {
+    pre[i] = pre[i - 1] + arr[i]
+  }
+  
+  let res = 0
+  if(pre[k - 1] / k >= threshold) res++
+  for(let i = k; i < n; i++) {
+    if(pre[i] - pre[i - k] >= k * threshold) res++
+  }
+  return res
+};