LeetCode 1099 Two Sum Less Than K - Easy

1099. Two Sum Less Than K — Easy

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Problem

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:
    def twoSumLessThanK(self, A: List[int], K: int) -> int:
        if not A:
            return -1
        
        A.sort()
        res = -1
        left, right = 0, len(A) - 1
        while left < right:
            if A[left] + A[right] >= K:
                right -= 1
            else:
                res = max(res, A[left] + A[right])
                left += 1
        return res