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Problem: Next Permutation

Medium
30 min
Explore how to find the next lexicographically greater permutation of an array using the two pointers approach. Understand how to rearrange elements in-place and apply this technique to solve common coding interview problems effectively.

Statement

Your task is to rearrange an array, nums, containing positive integers to form the next lexicographically greater permutationA permutation of an array of integers refers to any ordering of its elements into a sequence or linear arrangement.. This means finding the next permutation in the sequence of all possible arrangements sorted in dictionary order.

For example, given the array [4,5,6][4, 5, 6], the next permutation is [4,6,5][4, 6, 5]. In the same way, [5,6,4][5, 6, 4] becomes [6,4,5][6, 4, 5].

If the array is already in its highest possible order (sorted in descending order), such as [6,5,4][6, 5, 4], it’s not possible to find a lexicographically larger permutation. In this case, you must rearrange the array to its lowest possible order (sorted in ascending order), which would be [4,5,6][4, 5, 6].

The entire operation must be completed in-place while using only a constant amount of extra memory.

Constraints:

  • 11 \leq nums.length 100\leq 100

  • 00 \leq nums[i] 100\leq 100

Problem
Ask
Submissions

Problem: Next Permutation

Medium
30 min
Explore how to find the next lexicographically greater permutation of an array using the two pointers approach. Understand how to rearrange elements in-place and apply this technique to solve common coding interview problems effectively.

Statement

Your task is to rearrange an array, nums, containing positive integers to form the next lexicographically greater permutationA permutation of an array of integers refers to any ordering of its elements into a sequence or linear arrangement.. This means finding the next permutation in the sequence of all possible arrangements sorted in dictionary order.

For example, given the array [4,5,6][4, 5, 6], the next permutation is [4,6,5][4, 6, 5]. In the same way, [5,6,4][5, 6, 4] becomes [6,4,5][6, 4, 5].

If the array is already in its highest possible order (sorted in descending order), such as [6,5,4][6, 5, 4], it’s not possible to find a lexicographically larger permutation. In this case, you must rearrange the array to its lowest possible order (sorted in ascending order), which would be [4,5,6][4, 5, 6].

The entire operation must be completed in-place while using only a constant amount of extra memory.

Constraints:

  • 11 \leq nums.length 100\leq 100

  • 00 \leq nums[i] 100\leq 100