Algorithm Explanation

What the Algorithm Does

The algorithm maintains a dynamic window [left → right] such that:

The number of zeros inside the window is always ≤ K

Within this window:

• All elements can be treated as 1s (after flipping zeros)
• So, the window length = possible answer

Key Variables

• left → starting index of window
• right → ending index (moves forward)
• zero_count → number of 0s in current window
• max_length → stores the best answer

Sub Topic - 3: Step-by-Step Algorithm

Step 1: Initialization

Step 2: Expand the Window

Move right from 0 → n-1:

• If nums[right] == 0
  → increase zero_count

Step 3: Check Validity

• If zero_count ≤ K
  →  window is valid → continue expanding
• If zero_count > K
  →  window invalid → shrink from left

Step 4: Shrink the Window

While zero_count > K:

• If nums[left] == 0
  → decrease zero_count
• Move left++

This restores validity

Step 5: Update Answer

Visual Flow

Dry Run

Final Answer = 5

Why This Works

✔ We never restart
✔ Each element is processed at most twice
✔ Window always remains valid