995. Minimum Number of K Consecutive Bit Flips

 一刷 07/2022

Version #1 Sliding Window

感觉很难，照着答案写还是一知半解的感觉

Time O(N)

Space O(N)

Runtime: 11 ms, faster than 50.79% of Java online submissions for Minimum Number of K Consecutive Bit Flips.

Memory Usage: 92.1 MB, less than 74.80% of Java online submissions for Minimum Number of K Consecutive Bit Flips.

class Solution {

    public int minKBitFlips(int[] nums, int k) {

        // number of flips in the sliding window

        int flipCounter = 0;

        int flips = 0;

        boolean[] isFlipped = new boolean[nums.length];

        for (int i = 0; i < nums.length; i++) {

            if (i >= k && isFlipped[i - k]) {

                flipCounter--;

            }

            // check if we need to flip current bit

            if (flipCounter % 2 == nums[i]) {

                if (i + k > nums.length) {

                    return -1;

                }

                isFlipped[i] = true;

                flipCounter++;

                flips++;

            }

        }

        return flips;

    }

}