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46 lines
1.8 KiB
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46 lines
1.8 KiB
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<p>Given a <strong>0-indexed</strong> integer array <code>nums</code>, find the <strong>leftmost</strong> <code>middleIndex</code> (i.e., the smallest amongst all the possible ones).</p>
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<p>A <code>middleIndex</code> is an index where <code>nums[0] + nums[1] + ... + nums[middleIndex-1] == nums[middleIndex+1] + nums[middleIndex+2] + ... + nums[nums.length-1]</code>.</p>
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<p>If <code>middleIndex == 0</code>, the left side sum is considered to be <code>0</code>. Similarly, if <code>middleIndex == nums.length - 1</code>, the right side sum is considered to be <code>0</code>.</p>
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<p>Return <em>the <strong>leftmost</strong> </em><code>middleIndex</code><em> that satisfies the condition, or </em><code>-1</code><em> if there is no such index</em>.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<pre>
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<strong>Input:</strong> nums = [2,3,-1,<u>8</u>,4]
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<strong>Output:</strong> 3
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<strong>Explanation:</strong> The sum of the numbers before index 3 is: 2 + 3 + -1 = 4
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The sum of the numbers after index 3 is: 4 = 4
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</pre>
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<p><strong>Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> nums = [1,-1,<u>4</u>]
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<strong>Output:</strong> 2
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<strong>Explanation:</strong> The sum of the numbers before index 2 is: 1 + -1 = 0
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The sum of the numbers after index 2 is: 0
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</pre>
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<p><strong>Example 3:</strong></p>
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<pre>
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<strong>Input:</strong> nums = [2,5]
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<strong>Output:</strong> -1
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<strong>Explanation:</strong> There is no valid middleIndex.
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</pre>
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<p> </p>
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<p><strong>Constraints:</strong></p>
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<ul>
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<li><code>1 <= nums.length <= 100</code></li>
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<li><code>-1000 <= nums[i] <= 1000</code></li>
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</ul>
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<p> </p>
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<p><strong>Note:</strong> This question is the same as 724: <a href="https://leetcode.com/problems/find-pivot-index/" target="_blank">https://leetcode.com/problems/find-pivot-index/</a></p>
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