Competitions
Техника двух указателей
Sum of two
Given an array A, sorted in ascending order and containing n integers. Determine if there exists a pair of numbers (A_i, A_j), i < j, which sum is equal to x.
Input data
The first line contains two integers n\:(n \le 10^5) and x\:(x \le 10^6). The second line contains n non-negative integers, each of which is not greater than 10^6.
Output data
Print "YES" if such a pair of elements exists, and "NO" otherwise.
Examples
Input example #1
10 13 1 3 5 6 8 10 11 11 11 16
Output example #1
YES
Input example #2
8 61 5 5 8 12 16 21 44 50
Output example #2
NO