Sliding Window: Dynamic

def dynamic_sliding_window(nums, target):
    """
    Prints the steps of a dynamic sliding window algorithm.
    Given an array of positive integers and a target sum, the algorithm finds
    a contiguous subarray (window) whose sum is as close as possible to, but does not exceed, the target.
    """
    print("Problem: Given an array of positive integers and a target sum,")
    print("find a contiguous subarray whose sum is as close as possible to, but does not exceed, the target.")
    print(f"Example: nums = {nums}, target = {target}")
    print("-" * 70)

    left = 0
    current_sum = 0

    # Start processing the array with a sliding window
    for right in range(len(nums)):
        current_sum += nums[right]
        print(f"\nExpanding window: added nums[{right}] = {nums[right]}")
        print(f"Current window (indices [{left} to {right}]): {nums[left:right+1]}")
        print(f"Current sum: {current_sum}")

        # Contract the window from the left if the current sum exceeds the target.
        while current_sum > target and left <= right:
            print(f"  Sum {current_sum} exceeds target {target}. Removing nums[{left}] = {nums[left]}")
            current_sum -= nums[left]
            left += 1
            print(f"  After contraction, new window (indices [{left} to {right}]): {nums[left:right+1]}")
            print(f"  Current sum: {current_sum}")

    print("-" * 70)
    print(f"Final window (from index {left} to end): {nums[left:]}")
    print(f"Final sum: {current_sum}")


# Example usage:
nums = [1, 3, 2, 5, 1, 1, 2, 1, 4]
target = 8
dynamic_sliding_window(nums, target)