g0701_0800.s0775_global_and_local_inversions

Class Solution

java.lang.Object

g0701_0800.s0775_global_and_local_inversions.Solution

public class Solution
extends Object

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].

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
boolean	isIdealPermutation(int[] nums)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

isIdealPermutation

public boolean isIdealPermutation(int[] nums)