Problem

At Nordic Embedded, a microcontroller receives a stream of sensor flags where each reading is either 0 or 1. Because RAM is limited, write code that packs every 8 flags into one byte and returns the packed result using only constant extra working memory beyond the output array.

Formal Specification

Implement a function pack_sensor_flags(flags).

• Input: a list flags of integers, where each value is either 0 or 1
• Output: a list of integers in the range [0, 255]
• The first 8 flags form the first byte, the next 8 flags form the second byte, and so on.
• Within each byte, the earliest flag in the group should become the most significant bit.
• If the final group has fewer than 8 flags, pad the remaining low-order bits with 0.

Examples

Example 1

• Input: flags = [1,0,1,0,0,0,0,1]
• Output: [161]
• Explanation: The bits are 10100001, which equals 161.

Example 2

• Input: flags = [1,1,1,1,1,1,1,1, 0,0,0,0]
• Output: [255, 0]
• Explanation: The first 8 flags form 11111111 = 255. The remaining 4 flags become 00000000 after padding.

Constraints

• 0 <= len(flags) <= 10^5
• flags[i] is either 0 or 1
• Use O(1) extra working memory, excluding the returned output list