# Solving Leetcode Interviews in Seconds with AI: Find a Value of a Mysterious Function Closest to Target


	# Introduction
	In this blog post, we will explore how to solve the LeetCode problem "1521" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like [Chatmagic](https://www.chatmagic.app), we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

	# Problem Statement
	>  Winston was given the above mysterious function func. He has an integer array arr and an integer target and he wants to find the values l and r that make the value |func(arr, l, r) - target| minimum possible. Return the minimum possible value of |func(arr, l, r) - target|. Notice that func should be called with the values l and r where 0 <= l, r < arr.length.   Example 1:  Input: arr = [9,12,3,7,15], target = 5 Output: 2 Explanation: Calling func with all the pairs of [l,r] = [[0,0],[1,1],[2,2],[3,3],[4,4],[0,1],[1,2],[2,3],[3,4],[0,2],[1,3],[2,4],[0,3],[1,4],[0,4]], Winston got the following results [9,12,3,7,15,8,0,3,7,0,0,3,0,0,0]. The value closest to 5 is 7 and 3, thus the minimum difference is 2.  Example 2:  Input: arr = [1000000,1000000,1000000], target = 1 Output: 999999 Explanation: Winston called the func with all possible values of [l,r] and he always got 1000000, thus the min difference is 999999.  Example 3:  Input: arr = [1,2,4,8,16], target = 0 Output: 0    Constraints:  1 <= arr.length <= 105 1 <= arr[i] <= 106 0 <= target <= 107  

	# Explanation
	Here's a breakdown of the approach, followed by the code:

*   **Iterate and Calculate:** Iterate through all possible subarrays defined by `l` and `r` indices within the given array `arr`. For each subarray, calculate the result of the bitwise AND operation (`func` in the prompt) across the elements of the subarray.
*   **Minimize Difference:** Keep track of the minimum absolute difference between the calculated bitwise AND result and the target value.
*   **Return Minimum:** Return the minimized absolute difference.

*   **Runtime Complexity:** O(n^2), **Storage Complexity:** O(1)

	
	# Code
	```python
	def solve():
    arr = [int(x) for x in input().split()]
    target = int(input())

    def func(arr, l, r):
        result = arr[l]
        for i in range(l + 1, r + 1):
            result &= arr[i]
        return result

    min_diff = float('inf')
    for l in range(len(arr)):
        for r in range(l, len(arr)):
            val = func(arr, l, r)
            min_diff = min(min_diff, abs(val - target))

    print(min_diff)

# arr = [9,12,3,7,15]
# target = 5
# solve()

# arr = [1000000,1000000,1000000]
# target = 1
# solve()

# arr = [1,2,4,8,16]
# target = 0
# solve()

def solve2(arr, target):

    def func(arr, l, r):
        result = arr[l]
        for i in range(l + 1, r + 1):
            result &= arr[i]
        return result

    min_diff = float('inf')
    for l in range(len(arr)):
        for r in range(l, len(arr)):
            val = func(arr, l, r)
            min_diff = min(min_diff, abs(val - target))

    return min_diff
	```