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The D. E. Shaw GroupOA #4

Find Maximum Beauty

估计中等评测数据准备中,可先阅读题面

考点(AI 标注)子序列

Given an array arr, you can perform the following operation:

  • Remove an element from any position in the array. The order of other elements should be maintained after removing the element. You're allowed to perform this operation until the arr size becomes 1. Now the beauty of an array is equal to the number of elements where a[i] = i (the array is 1 indexed). Given an array, find the maximum beauty after performing the above operation. Function Description Complete the function findMaximumBeauty in the editor. findMaximumBeauty has the following parameter:
  • int[] arr: an array of integers Returns int: the maximum beauty of the array

Constraints

unknown for now

Example 1

Input:

arr = [1, 3, 2, 5, 4, 5, 3]

Output:

4

Explanation: Following the operations described in the problem statement:

  • Remove the first 3, then arr becomes [1, 2, 5, 4, 5, 3].
  • Remove 3, then arr becomes [1, 2, 5, 4, 5]. The beauty of the final array is 4. (where a[i] = i).