2379. Minimum Recolors to Get K Consecutive Black Blocks LeetCode Solution

In this guide, you will get 2379. Minimum Recolors to Get K Consecutive Black Blocks LeetCode Solution with the best time and space complexity. The solution to Minimum Recolors to Get K Consecutive Black Blocks problem is provided in various programming languages like C++, Java, and Python. This will be helpful for you if you are preparing for placements, hackathons, interviews, or practice purposes. The solutions provided here are very easy to follow and include detailed explanations.

Table of Contents

1. Problem Statement
2. Complexity Analysis
3. Minimum Recolors to Get K Consecutive Black Blocks solution in C++
4. Minimum Recolors to Get K Consecutive Black Blocks solution in Java
5. Minimum Recolors to Get K Consecutive Black Blocks solution in Python
6. Additional Resources

Problem Statement of Minimum Recolors to Get K Consecutive Black Blocks

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 = 7
Output: 3
Explanation:
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 = 2
Output: 0
Explanation:
No changes need to be made, since 2 consecutive black blocks already exist.
Therefore, we return 0.

Constraints:

n == blocks.length
1 <= n <= 100
blocks[i] is either 'W' or 'B'.
1 <= k <= n

Complexity Analysis

• Time Complexity: O(n)
• Space Complexity: O(1)

2379. Minimum Recolors to Get K Consecutive Black Blocks LeetCode Solution in C++

class Solution {
 public:
  int minimumRecolors(string blocks, int k) {
    int countB = 0;
    int maxCountB = 0;

    for (int i = 0; i < blocks.length(); ++i) {
      if (blocks[i] == 'B')
        ++countB;
      if (i >= k && blocks[i - k] == 'B')
        --countB;
      maxCountB = max(maxCountB, countB);
    }

    return k - maxCountB;
  }
};
/* code provided by PROGIEZ */

2379. Minimum Recolors to Get K Consecutive Black Blocks LeetCode Solution in Java

class Solution {
  public int minimumRecolors(String blocks, int k) {
    int countB = 0;
    int maxCountB = 0;

    for (int i = 0; i < blocks.length(); ++i) {
      if (blocks.charAt(i) == 'B')
        ++countB;
      if (i >= k && blocks.charAt(i - k) == 'B')
        --countB;
      maxCountB = Math.max(maxCountB, countB);
    }

    return k - maxCountB;
  }
}
// code provided by PROGIEZ

2379. Minimum Recolors to Get K Consecutive Black Blocks LeetCode Solution in Python

class Solution:
  def minimumRecolors(self, blocks: str, k: int) -> int:
    countB = 0
    maxCountB = 0

    for i, block in enumerate(blocks):
      if block == 'B':
        countB += 1
      if i >= k and blocks[i - k] == 'B':
        countB -= 1
      maxCountB = max(maxCountB, countB)

    return k - maxCountB
 # code by PROGIEZ

Additional Resources

• Explore all LeetCode problem solutions at Progiez here
• Explore all problems on LeetCode website here

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