An array is squareful if the sum of every pair of adjacent elements is a perfect square.
Given an integer array nums, return the number of permutations of nums that are squareful.
Two permutations perm1 and perm2 are different if there is some index i such that perm1[i] != perm2[i].
Examples
Example 1
Input: nums = [1,17,8]
Output: 2
Explanation: [1,8,17] and [17,8,1] are the valid permutations.
Example 2
Input: nums = [2,2,2]
Output: 1
Constraints
1 <= nums.length <= 12
0 <= nums[i] <= 109
996. Number of Squareful Arrays
Hard
50 Points
Array
Hash Table
Math
Dynamic Programming
Backtracking
Bit Manipulation
Bitmask
An array is squareful if the sum of every pair of adjacent elements is a perfect square.
Given an integer array nums, return the number of permutations of nums that are squareful.
Two permutations perm1 and perm2 are different if there is some index i such that perm1[i] != perm2[i].
Examples
Example 1
Input: nums = [1,17,8]
Output: 2
Explanation: [1,8,17] and [17,8,1] are the valid permutations.
Example 2
Input: nums = [2,2,2]
Output: 1
Constraints
1 <= nums.length <= 12
0 <= nums[i] <= 109
Number of Squareful Arrays - Practice Coding | SlaveCode