g2701_2800.s2780_minimum_index_of_a_valid_split.Solution

public class Solution extends Object

2780 - Minimum Index of a Valid Split.Medium An element <code>x</code> of an integer array <code>arr</code> of length <code>m</code> is dominant if <code>freq(x) * 2 > m</code>, where <code>freq(x)</code> is the number of occurrences of <code>x</code> in <code>arr</code>. Note that this definition implies that <code>arr</code> can have at most one dominant element. You are given a 0-indexed integer array <code>nums</code> of length <code>n</code> with one dominant element. You can split <code>nums</code> at an index <code>i</code> into two arrays <code>nums[0, ..., i]</code> and <code>nums[i + 1, ..., n - 1]</code>, but the split is only valid if: <ul> <li><code>0 <= i < n - 1</code></li> <li><code>nums[0, ..., i]</code>, and <code>nums[i + 1, ..., n - 1]</code> have the same dominant element.</li> </ul> Here, <code>nums[i, ..., j]</code> denotes the subarray of <code>nums</code> starting at index <code>i</code> and ending at index <code>j</code>, both ends being inclusive. Particularly, if <code>j < i</code> then <code>nums[i, ..., j]</code> denotes an empty subarray. Return the minimum index of a valid split. If no valid split exists, return <code>-1</code>. Example 1: Input: nums = [1,2,2,2] Output: 2 Explanation: We can split the array at index 2 to obtain arrays [1,2,2] and [2]. In array [1,2,2], element 2 is dominant since it occurs twice in the array and 2 * 2 > 3. In array [2], element 2 is dominant since it occurs once in the array and 1 * 2 > 1. Both [1,2,2] and [2] have the same dominant element as nums, so this is a valid split. It can be shown that index 2 is the minimum index of a valid split. Example 2: Input: nums = [2,1,3,1,1,1,7,1,2,1] Output: 4 Explanation: We can split the array at index 4 to obtain arrays [2,1,3,1,1] and [1,7,1,2,1]. In array [2,1,3,1,1], element 1 is dominant since it occurs thrice in the array and 3 * 2 > 5. In array [1,7,1,2,1], element 1 is dominant since it occurs thrice in the array and 3 * 2 > 5. Both [2,1,3,1,1] and [1,7,1,2,1] have the same dominant element as nums, so this is a valid split. It can be shown that index 4 is the minimum index of a valid split. Example 3: Input: nums = [3,3,3,3,7,2,2] Output: -1 Explanation: It can be shown that there is no valid split. Constraints: <ul> <li><code>1 <= nums.length <= 105</code></li> <li><code>1 <= nums[i] <= 109</code></li> <li><code>nums</code> has exactly one dominant element.</li> </ul>

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Solution()
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int

minimumIndex(List<Integer> nums)

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- Solution
  
  public Solution()
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- minimumIndex
 
 public int minimumIndex(List<Integer> nums)

Class Solution

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Solution

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minimumIndex