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Java-based LeetCode algorithm problem solutions, regularly updated
775\. Global and Local Inversions
Medium
You are given an integer array `nums` of length `n` which represents a permutation of all the integers in the range `[0, n - 1]`.
The number of **global inversions** is the number of the different pairs `(i, j)` where:
* `0 <= i < j < n`
* `nums[i] > nums[j]`
The number of **local inversions** is the number of indices `i` where:
* `0 <= i < n - 1`
* `nums[i] > nums[i + 1]`
Return `true` _if the number of **global inversions** is equal to the number of **local inversions**_.
**Example 1:**
**Input:** nums = [1,0,2]
**Output:** true
**Explanation:** There is 1 global inversion and 1 local inversion.
**Example 2:**
**Input:** nums = [1,2,0]
**Output:** false
**Explanation:** There are 2 global inversions and 1 local inversion.
**Constraints:**
* `n == nums.length`
* 1 <= n <= 105
* `0 <= nums[i] < n`
* All the integers of `nums` are **unique**.
* `nums` is a permutation of all the numbers in the range `[0, n - 1]`.