atcoder_my_template.ts

declare global {interface Object { log<T>(this: T, msg?): T }} // prettier-ignore

export function main(input: string): number | string {
  const [A, B] = input.split(/\s/).map(Number);
  return input;
}

// === ここから読む必要なし ===
const DEBUG = process.env.NODE_ENV === "test";
Object.assign(Object.prototype,{log<T>(this:T,msg="log"){if(DEBUG)console.log(`[${msg}] ${this}`);return this}}) // prettier-ignore
if (!DEBUG) {
  if (process.send) console.log(main(require("fs").readFileSync(0, "utf8").trim()));
  else require("child_process").fork(__filename, { execArgv: ["--stack-size=99900"] });
}

launch.json

{
  "configurations": [
    {
      "name": "Launch TypeScript Using ts-node",
      "type": "node",
      "request": "launch",
      "env": { "NODE_ENV": "test" },
      "skipFiles": ["<node_internals>/**", "node_modules/**"],
      "runtimeArgs": ["--stack-size=99900", "--nolazy", "-r", "ts-node/register"],
      "program": "${file}"
    }
  ]
}

もうすでにけっこう変わってます。まとめなおす気は・・・・・