# Write a Program to Find the Distinct Difference Array

# 2670. Find the Distinct Difference Array

You are given a 0-indexed array nums of length n.

The distinct difference array of nums is an array diff of length n such that diff[i] is equal to the number of distinct elements in the suffix nums[i + 1, …, n – 1] subtracted from the number of distinct elements in the prefix nums[0, …, i].

Return the distinct difference array of nums.

Note that nums[i, …, j] denotes the subarray of nums starting at index i and ending at index j inclusive. Particularly, if i > j then nums[i, …, j] denotes an empty subarray.

### Example 1: ``` Input: nums = [1,2,3,4,5] Output: [-3,-1,1,3,5] Explanation: For index i = 0, there is 1 element in the prefix and 4 distinct elements in the suffix. Thus, diff[0] = 1 - 4 = -3. For index i = 1, there are 2 distinct elements in the prefix and 3 distinct elements in the suffix. Thus, diff[1] = 2 - 3 = -1. For index i = 2, there are 3 distinct elements in the prefix and 2 distinct elements in the suffix. Thus, diff[2] = 3 - 2 = 1. For index i = 3, there are 4 distinct elements in the prefix and 1 distinct element in the suffix. Thus, diff[3] = 4 - 1 = 3. For index i = 4, there are 5 distinct elements in the prefix and no elements in the suffix. Thus, diff[4] = 5 - 0 = 5. ```

### Example 2: ``` Input: nums = [3,2,3,4,2] Output: [-2,-1,0,2,3] Explanation: For index i = 0, there is 1 element in the prefix and 3 distinct elements in the suffix. Thus, diff[0] = 1 - 3 = -2. For index i = 1, there are 2 distinct elements in the prefix and 3 distinct elements in the suffix. Thus, diff[1] = 2 - 3 = -1. For index i = 2, there are 2 distinct elements in the prefix and 2 distinct elements in the suffix. Thus, diff[2] = 2 - 2 = 0. For index i = 3, there are 3 distinct elements in the prefix and 1 distinct element in the suffix. Thus, diff[3] = 3 - 1 = 2. For index i = 4, there are 3 distinct elements in the prefix and no elements in the suffix. Thus, diff[4] = 3 - 0 = 3. ```

Constraints: ``` 1 <= n == nums.length <= 50 1 <= nums[i] <= 50 ```

/** * @param {number[]} nums * @return {number[]} */ const distinctDifferenceArray = function(nums) { const out = []; for(let i = 0; i < nums.length; i ++) { const first = new Set(nums.slice(0, i+1)); const last = new Set(nums.slice(i+1)); out.push(first.size - last.size); } return out; };