Leetcode 2379. Minimum Recolors to Get K Consecutive Black Block
You are given a?0-indexed?string?blocks?of length?n, where?blocks[i]?is either?'W'?or?'B', representing the color of the?ith?block. The characters?'W'?and?'B'?denote the colors white and black, respectively.
You are also given an integer?k, which is the desired number of?consecutive?black blocks.
In one operation, you can?recolor?a white block such that it becomes a black block.
Return?the?minimum?number of operations needed such that there is at least?one?occurrence of?k?consecutive black blocks.
?
Example 1:
Input: blocks = "WBBWWBBWBW", k = 7Output: 3Explanation:One way to achieve 7 consecutive black blocks is to recolor the 0th, 3rd, and 4th blocks so that blocks = "BBBBBBBWBW". It can be shown that there is no way to achieve 7 consecutive black blocks in less than 3 operations. Therefore, we return 3.
Example 2:
Input: blocks = "WBWBBBW", k = 2Output: 0Explanation:No changes need to be made, since 2 consecutive black blocks already exist. Therefore, we return 0.
?
Constraints:
n == blocks.length1 <= n <= 100blocks[i]?is either?'W'?or?'B'.1 <= k <= n
使用前綴和的時(shí)候，要多一個(gè)位置，這也是就一直沒(méi)解決的原因，尷尬；
同時(shí)也可以使用sliding window來(lái)解決；
Runtime:?1 ms, faster than?85.02%?of?Java?online submissions for?Minimum Recolors to Get K Consecutive Black Blocks.
Memory Usage:?40.4 MB, less than?52.26%?of?Java?online submissions for?Minimum Recolors to Get K Consecutive Black Blocks.
