Smallest Subarray With Sum

You are given an array of integers nums and an integer k. Your task is to find the length L of the smallest contiguous subarray such that its sum is greater than or equal to k. If no such subarray exists, output -1.

Formally, you need to find the minimum L (with L ≥ 1) such that there exists an index i with

$\displaystyle \sum_{j=i}^{i+L-1} nums[j] \ge k$

If there exists no subarray satisfying the condition, return -1.

inputFormat

The input is given via stdin in the following format:

a1 a2 a3 ... an
k

Where:

• n is a positive integer representing the number of elements in the array.
• a1, a2, ..., an are the integers of the array nums, separated by spaces.
• k is the target sum.

outputFormat

Output a single integer to stdout which is the length of the smallest contiguous subarray with sum greater than or equal to k. If no such subarray exists, output -1.

## sample

5
1 2 3 4 5
11

3

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