In an array `nums`

containing only 0s and 1s, a * k-bit flip *consists of choosing a (contiguous) subarray of length

`k`

and simultaneously changing every 0 in the subarray to 1, and every 1 in the subarray to 0.Return the minimum number of `k`

-bit flips required so that there is no 0 in the array. If it is not possible, return `-1`

.

**Example 1:**

Input:nums = [0,1,0], k = 1Output:2Explanation:Flip nums[0], then flip nums[2].

**Example 2:**

Input:nums = [1,1,0], k = 2Output:-1Explanation:No matter how we flip subarrays of size 2, we can't make the array become [1,1,1].

**Example 3:**

Input:nums = [0,0,0,1,0,1,1,0], k = 3Output:3Explanation:Flip nums[0],nums[1],nums[2]: nums becomes [1,1,1,1,0,1,1,0] Flip nums[4],nums[5],nums[6]: nums becomes [1,1,1,1,1,0,0,0] Flip nums[5],nums[6],nums[7]: nums becomes [1,1,1,1,1,1,1,1]

**Note:**

`1 <= nums.length <= 30000`

`1 <= k <= nums.length`

class Solution {
public int minKBitFlips(int[] nums, int k) {
}
}