3 Sum

Given an array A of N integers, find three integers in A such that the sum is closest to a given number B. Return the sum of those three integers.

Assume that there will only be one solution.

• -3 * 10⁸ <= B <= 3 * 10⁸
• 1 <= N <= 10⁴
• -10⁸ <= A[i] <= 10⁸

First argument is an integer array A of size N.

Second argument is an integer B denoting the sum you need to get close to.

Return a single integer denoting the sum of three integers which is closest to B.

Input 1:

A = [-1, 2, 1, -4]
B = 1

Input 2:

 
A = [1, 2, 3]
B = 6

Output 1:

2

Output 2:

6

Explanation 1:

 The sum that is closest to the target is 2. (-1 + 2 + 1 = 2)

Explanation 2:

 Take all elements to get exactly 6.