1099.Two-Sum-Less-Than-K

1099. Two Sum Less Than K

题目地址

题目描述

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

代码

Approach 1: Two Point

class Solution {
public int twoSumLessThanK(int[] A, int K) {
Arrays.sort(A);
int i = 0;
int j = A.length - 1;
int ans = -1;
while (i < j) {
if (A[i] + A[j] >= K) {
j--;
} else {
ans = Math.max(ans, A[i] + A[j]);
i++;
}
}
return ans;
}
}