Problem Brief

Minimum Flips to Alternate Binary String (With K Flip Window)

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You are given a binary string s. In one operation, you can flip a subarray of length exactly k (flip all bits in that subarray). Return the minimum number of such operations needed to make the string alternating (i.e., no two adjacent bits are the same). If it's not possible, return -1.

1Example 1

Input

s = "00010111", k = 3

Output

Explanation

^~^

Draft autosaves locally

public int minFlips(String s, int k) {
  // write your code here
}

Input

"00010111"

Output