Subarray Sum Existence

You are given an array of n integers and a target integer k. Your task is to determine whether there exists a contiguous subarray whose sum is exactly k.

Formally, given an array A of size n, determine if there exist indices l and r (with 1 ≤ l ≤ r ≤ n) such that:

\(A[l] + A[l+1] + \cdots + A[r] = k\)

If such a subarray exists, output YES. Otherwise, output NO.

Example:
For n = 5, A = [1, 2, 3, 4, 5] and k = 15, the entire array sums to 15, so the answer is YES.

inputFormat

The input is given via standard input (stdin) and has the following format:

• The first line contains two integers n and k, where n is the number of elements in the array and k is the target sum.
• The second line contains n space-separated integers representing the elements of the array.

outputFormat

Print a single line to standard output (stdout) containing YES if there exists a contiguous subarray with sum equal to k, or NO otherwise.

5 15
1 2 3 4 5

YES