# Question

Formatted question description: https://leetcode.ca/all/1099.html


Given an array A of integers and integer K,
return the maximum S such that there exists
i < j with
A[i] + A[j] = S and
S < K.
If no i, j, exist satisfying this equation, return -1.

Example 1:

Input: A = [34,23,1,24,75,33,54,8], K = 60
Output: 58
Explanation:
We can use 34 and 24 to sum 58 which is less than 60.

Example 2:

Input: A = [10,20,30], K = 15
Output: -1
Explanation:
In this case it's not possible to get a pair sum less that 15.

Note:
1 <= A.length <= 100
1 <= A[i] <= 1000
1 <= K <= 2000



# Algorithm

(brute force) O(n^2)

Enumerate i and j, and then find the maximum value less than K.

time complexity

• Two-level loop traversal, so the time complexity is O(n^2)).

Space complexity

• Only a constant number of traversals are needed, so the space complexity is O(1).

Java