Chapter 177: Threshold and Margin

The cold glow of the screen washed over his face. In the dorm, only the low hum of the PC fan and the faint clatter of the keyboard broke the silence. Lin Chen propped his left foot on a stack of old cotton quilts. The swelling had long since swallowed the outline of his shoe, the skin stretched taut and shiny, revealing a web of dark red capillaries. He unrolled the last strip of elastic bandage and began wrapping from the instep upward. His movements were deliberate and slow—careful not to compress the already numb superficial peroneal nerve, yet tight enough to prevent impeded venous return. By the third wrap, a dull ache shot through his toes, like fine needles scraping along the bone seams. He paused, adjusted the angle, folded the bandage’s edge inward by half an inch, and continued.

Spread across the desk were two A4 sheets. On the left lay a photocopy of the acceptance report for the Provincial Institute of Metrology project; on the right, a blank resume template. He stared at the “Project Experience” section, the cursor blinking rhythmically in the empty space. The factory code couldn’t just be pasted in. Scripts for industrial sites prioritized “runs, doesn’t crash, logs everything,” but the job description Professor Zhou had forwarded demanded “high concurrency, modularity, unit testing, version control.” He opened the shenzhen_intern folder, dragged the V3.1 cleaning script into a newly created data_pipeline directory, and began refactoring.

First, he stripped out the hardcoded absolute paths, replacing them with relative paths and config file reads. He extracted the exception-handling blocks scattered throughout the main program into a standalone error_handler module. With every line he changed, a spasm shot through his left foot. He bit down on his lower lip, but his fingers never stopped. The code on the screen gradually fell into order: function names shifted from fix_data to normalize_phase_offset, variables from tmp1 to sync_error_ms. He added docstrings, explicitly detailing input and output data types along with boundary conditions. This wasn’t for aesthetics; it was so someone else could actually read it. Code at an internet company isn’t written for yourself—it’s written for the next person who inherits it. He understood this as clearly as he understood that three-phase power in a workshop had to be balanced.

At nine o’clock, the clamor of roommates and the smell of instant noodles drifted down the hallway. Lin Chen put on his headphones, shutting out the world. He opened a terminal, initialized a Git repository, configured .gitignore, and excluded build caches and temporary log files. For the first commit, he kept the message dry: feat: refactor data cleaning pipeline, encapsulate phase compensation logic, add basic logging module. The progress bar crawled upward. The dorm light flickered—voltage instability. Habitually, he reached for the power strip at the corner of his desk to check the connections. The old campus wiring was aging, and breakers frequently tripped during the evening peak. He had already fully charged his laptop battery and plugged the external hard drive from his shockproof case into a backup power supply. It couldn’t disconnect. If it did, the commit history would be corrupted.

By eleven-thirty, the resume draft was complete. Education, tech stack, project descriptions. He changed “manually calibrated errors” to “implemented a millisecond-level phase offset compensation algorithm, increasing data integrity to 99.2%.” He changed “debugged through the night” to “independently managed on-site hotfixes, completing register mapping corrections without system downtime.” The text was cold, stripped of adjectives, relying solely on verbs and numbers. He exported it as a PDF, naming it LinChen_Intern_2010.pdf. File size: 1.4 MB. He opened the referral link and filled out the form item by item: name, student ID, email, GitHub profile. Before pasting the link, he double-checked the repository’s README to ensure no internal factory parameters had leaked and no plaintext test passwords remained. He clicked submit. The page redirected: “Application received. Expected feedback within 3–5 working days.”

He stared at those words without refreshing the page. Closed the browser, cleared the cache. Locked the original acceptance report from the shockproof case into his desk drawer. His phone screen lit up: bank balance, 7,135.30. He opened the calculator. Hard seat to Shenzhen: 186. Urban village apartment, one month deposit plus three months rent: roughly 2,400. First month living expenses: 1,500. Follow-up clinic registration and medication: 300. Reserve fund: 800. Total: approximately 5,426. It was enough on paper, but the margin was compressed to the absolute limit. His brother’s sodium valproate would run out next month. On their last call, his mother had mentioned that the notice for the new rural cooperative medical insurance premiums had already been posted on the village bulletin board. He crossed out the reserve fund and changed it to 600. Numbers were just numbers; only when entered into the ledger did they become daily life. He closed the calculator, stood up, and headed to the washroom for cold water.

He hopped on one leg, his right foot landing heavily. In the washroom, a faucet dripped, the sound echoing through the empty corridor. He soaked a towel in cold water and pressed it against his ankle. The biting chill suppressed the burning pain. Leaning back against the tiled wall, he closed his eyes. His mind wasn’t on code, but on the line from Professor Zhou’s email: “Opportunity comes only once.” He knew exactly what that meant. It wasn’t an elevator; it was a staircase. You had to climb it yourself. And while climbing, you couldn’t look down, and you couldn’t stop.

At one in the morning, the dorm was completely silent. He returned to his seat. The screen had gone to sleep. He tapped the spacebar to wake it. Just as he was about to shut down, a new email notification popped up in the bottom right corner. It wasn’t from HR, but an automated system reply containing a test link. Subject: [Technical Screening] Online Coding Test – Please Complete Within 48 Hours. The attachment contained an algorithm problem: Given a time-series dataset containing phase noise, design a sliding window filtering algorithm with a time complexity of O(n) and a space complexity of O(1). Below the prompt, a line of small print read: “The test environment is Linux. Please submit an executable script and a performance report. Timeouts or memory overflows will be considered a failure.”

He opened the attachment and dragged the problem into his local editor. His left foot began to burn, the edge of the bandage seeping dark yellow ointment. He sat up straight, created a new .py file, and let his fingers rest on the keyboard. Outside, the sky was still pitch black, but the distant streetlights had already gone out. He knew the next round of assessment wouldn’t happen on the factory floor, but inside a server. He typed the first line: import sys. The screen’s light reflected in his pupils. Utterly quiet.