Sync LeetCode submission Runtime - 90 ms (22.05%), Memory - 33 MB (29.18%)

Author: jimit105

2358-number-of-ways-to-split-array/README.md

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+<p>You are given a <strong>0-indexed</strong> integer array <code>nums</code> of length <code>n</code>.</p>
+
+<p><code>nums</code> contains a <strong>valid split</strong> at index <code>i</code> if the following are true:</p>
+
+<ul>
+	<li>The sum of the first <code>i + 1</code> elements is <strong>greater than or equal to</strong> the sum of the last <code>n - i - 1</code> elements.</li>
+	<li>There is <strong>at least one</strong> element to the right of <code>i</code>. That is, <code>0 &lt;= i &lt; n - 1</code>.</li>
+</ul>
+
+<p>Return <em>the number of <strong>valid splits</strong> in</em> <code>nums</code>.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums = [10,4,-8,7]
+<strong>Output:</strong> 2
+<strong>Explanation:</strong> 
+There are three ways of splitting nums into two non-empty parts:
+- Split nums at index 0. Then, the first part is [10], and its sum is 10. The second part is [4,-8,7], and its sum is 3. Since 10 &gt;= 3, i = 0 is a valid split.
+- Split nums at index 1. Then, the first part is [10,4], and its sum is 14. The second part is [-8,7], and its sum is -1. Since 14 &gt;= -1, i = 1 is a valid split.
+- Split nums at index 2. Then, the first part is [10,4,-8], and its sum is 6. The second part is [7], and its sum is 7. Since 6 &lt; 7, i = 2 is not a valid split.
+Thus, the number of valid splits in nums is 2.
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> nums = [2,3,1,0]
+<strong>Output:</strong> 2
+<strong>Explanation:</strong> 
+There are two valid splits in nums:
+- Split nums at index 1. Then, the first part is [2,3], and its sum is 5. The second part is [1,0], and its sum is 1. Since 5 &gt;= 1, i = 1 is a valid split. 
+- Split nums at index 2. Then, the first part is [2,3,1], and its sum is 6. The second part is [0], and its sum is 0. Since 6 &gt;= 0, i = 2 is a valid split.
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>2 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
+	<li><code>-10<sup>5</sup> &lt;= nums[i] &lt;= 10<sup>5</sup></code></li>
+</ul>

2358-number-of-ways-to-split-array/solution.py

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+# Approach 1: Prefix Sum Array
+
+# Time: O(n)
+# Space: O(n)
+
+class Solution:
+    def waysToSplitArray(self, nums: List[int]) -> int:
+        n = len(nums)
+        prefix_sum = [0] * n
+        prefix_sum[0] = nums[0]
+
+        for i in range(1, n):
+            prefix_sum[i] = prefix_sum[i - 1] + nums[i]
+
+        # Check each possible split position
+        count = sum(1 for i in range(n - 1) if prefix_sum[i] >= prefix_sum[-1] - prefix_sum[i])
+
+        return count
+