Sync LeetCode submission Runtime - 127 ms (37.28%), Memory - 30.6 MB (31.97%)

Author: jimit105

2394-count-subarrays-with-score-less-than-k/README.md

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+<p>The <strong>score</strong> of an array is defined as the <strong>product</strong> of its sum and its length.</p>
+
+<ul>
+	<li>For example, the score of <code>[1, 2, 3, 4, 5]</code> is <code>(1 + 2 + 3 + 4 + 5) * 5 = 75</code>.</li>
+</ul>
+
+<p>Given a positive integer array <code>nums</code> and an integer <code>k</code>, return <em>the <strong>number of non-empty subarrays</strong> of</em> <code>nums</code> <em>whose score is <strong>strictly less</strong> than</em> <code>k</code>.</p>
+
+<p>A <strong>subarray</strong> is a contiguous sequence of elements within an array.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums = [2,1,4,3,5], k = 10
+<strong>Output:</strong> 6
+<strong>Explanation:</strong>
+The 6 subarrays having scores less than 10 are:
+- [2] with score 2 * 1 = 2.
+- [1] with score 1 * 1 = 1.
+- [4] with score 4 * 1 = 4.
+- [3] with score 3 * 1 = 3. 
+- [5] with score 5 * 1 = 5.
+- [2,1] with score (2 + 1) * 2 = 6.
+Note that subarrays such as [1,4] and [4,3,5] are not considered because their scores are 10 and 36 respectively, while we need scores strictly less than 10.</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums = [1,1,1], k = 5
+<strong>Output:</strong> 5
+<strong>Explanation:</strong>
+Every subarray except [1,1,1] has a score less than 5.
+[1,1,1] has a score (1 + 1 + 1) * 3 = 9, which is greater than 5.
+Thus, there are 5 subarrays having scores less than 5.
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
+	<li><code>1 &lt;= nums[i] &lt;= 10<sup>5</sup></code></li>
+	<li><code>1 &lt;= k &lt;= 10<sup>15</sup></code></li>
+</ul>

2394-count-subarrays-with-score-less-than-k/solution.py

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+# Approach: Sliding Window
+
+# Time: O(n)
+# Space: O(1)
+
+class Solution:
+    def countSubarrays(self, nums: List[int], k: int) -> int:
+        n = len(nums)
+        res, total = 0, 0
+        i = 0
+
+        for j in range(n):
+            total += nums[j]
+            while i <= j and total * (j - i + 1) >= k:
+                total -= nums[i]
+                i += 1
+            res += j - i + 1
+
+        return res