Closest Pair Sum

Difficulty: 1500 3500 ms 128 MB

sorting two-pointers

Choose two different elements whose sum is as close as possible to the target T. Print that sum; if two sums are equally close, print the smaller sum.

Input: the first line has N and T; the second line has N integers.

Output: the achievable pair sum closest to T (smaller one on ties).

Constraints:

• 2 ≤ N ≤ 10⁵
• |a_i|, |T| ≤ 2×10⁹

Sample Tests

5 10
1 3 5 8 12

9

2 0
-3 9

6

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