"What are you going to do with all these photos?"
Riku looked at Yuki's smartphone.
"I want to preserve memories," Yuki answered.
Aoi showed interest. "But storage is finite."
"I know. That's why I delete them sometimes."
"That's the essence of compression," Aoi said.
"Compression?" Riku asked.
"Technology to reduce information amount for storage. There's lossless and lossy compression."
Aoi wrote on the whiteboard.
"Lossless compression: Can be fully restored Lossy compression: Can only be approximately restored"
Yuki thought. "Deleting photos is lossy?"
"Yes. Once deleted, it can't be fully recovered. Memory is the same."
Riku asked curiously. "But human memory gets compressed automatically, right?"
"Good observation," Aoi nodded. "The brain automatically performs lossy compression. Retains important information, discards details."
"That's why old memories are vague," Yuki understood.
"Exactly. Like Huffman codes, it prioritizes high-frequency information."
Aoi drew a diagram.
"High importance → Short code → Retained Low importance → Long code → Forgotten"
Riku laughed. "My brain's compression rate is too high, I forget test material."
"That's just a bad compression algorithm," Aoi pointed out.
Yuki asked. "Is lossless compression better?"
"Depends. Lossless is accurate but has low compression rate. Lossy has high compression rate but loses information."
"It's a tradeoff."
"Yes. JPEG is lossy, PNG is lossless. Choose based on purpose."
Riku pondered. "So should we compress youth too?"
"It's already compressed," Aoi answered. "When it's saved as memory."
"But if we compress too much, we lose important things," Yuki said.
"That's why balance is important. Keep moderate redundancy."
Aoi drew another diagram.
"Perfect memory: Requires enormous capacity Moderate compression: Retains important information Excessive compression: Meaning is lost"
Yuki looked at the smartphone. "I don't need to keep all photos."
"Choose what's important. That's the essence of compression."
Riku said seriously. "But we don't know what's important now."
"Sharp point," Aoi was impressed. "Finding the optimal compression algorithm is difficult."
"That's why people write diaries and take photos," Yuki understood.
"External storage. Supplements brain compression."
Riku looked outside. The sun was setting.
"This moment too will be compressed someday."
"Yes. But important moments remain even when compressed," Aoi said quietly.
Yuki closed the notebook. "We can choose our own youth compression algorithm."
"We can and should. What to keep and what to discard."
"It's a difficult choice."
"That's why it's youth," Aoi smiled.
The three quietly left the classroom. Today's memory will also be compressed someday. But the essence of this conversation will remain.
That's the result of the youth compression algorithm.