Amazon Online Assessment (OA) - Optimal Utilization
Given two lists a and b.
Each element is a pair of integers where the first integer represents the unique id and the second integer represents a value.
Your task is to find an element from a and an element form b such that the sum of their values is less or equal to target and as close to target as possible.
Return a list of ids of selected elements. If no pair is possible, return an empty list.
Input
a, a list of integer pairs where the first integer represents the unique id and the second integer represents a value.
b, a list of integer pairs where the first integer represents the unique id and the second integer represents a value.
target, an integer representing the target number.
Examples
Example 1:
Input:
a = [[1, 2], [2, 4], [3, 6]],
b = [[1, 2]],
target = 7,
Output: [[2, 1]]
Explanation:
There are only three combinations [1, 1], [2, 1], and [3, 1], which have a total sum of 4, 6 and 8, respectively.
Since 6 is the largest sum that does not exceed 7, [2, 1] is the optimal pair.
Example 2:
Input:
a = [[1, 3], [2, 5], [3, 7], [4, 10]],
b = [[1, 2], [2, 3], [3, 4], [4, 5]],
target = 10,
Output: [[2, 4], [3, 2]]
Explanation:
There are two pairs possible. Element with id = 2 from the list a has a value 5, and element with id = 4 from the list b also has a value 5.
Combined, they add up to 10. Similarly, element with id = 3 from a has a value 7, and element with id = 2 from b has a value 3.
These also add up to 10. Therefore, the optimal pairs are [2, 4] and [3, 2].
Example 3:
Input:
a = [[1, 8], [2, 7], [3, 14]],
b = [[1, 5], [2, 10], [3, 14]],
target = 20,
Output: [[3, 1]]
Example 4:
Input:
a = [[1, 8], [2, 15], [3, 9]],
b = [[1, 8], [2, 11], [3, 12]],
target = 20,