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
Solution:
class Solution {
public int twoSumLessThanK(int[] A, int K) {
TreeSet<Integer> set = new TreeSet();
int result = -1;
for (int i = 0; i < A.length; i ++) {
int val = A[i];
Integer floor = set.floor(K - val - 1);
if (floor != null) {
result = Math.max(result, val + floor);
}
set.add(val);
}
return result;
}
}