Code Review (Easy): The Permission Audit

Story

Lena was refining the team’s internal permissions tool to help audit every possible combination of access tags assigned to developers. Mark noticed that several accounts often have identical roles, such as two 'Guest' tags, and he asked Lena to ensure that the final report doesn't list the same grouping of tags more than once. For instance, if a developer has one 'Admin' tag and two 'Guest' tags, the tool should generate every unique bundle of these tags—like a single 'Guest' tag or the full set of all three—while carefully avoiding any repeated results.

Your Task

Read the story and code, then decide if the code is ready for production or needs improvement.

Hints

What would block an approval? Give me a hint.

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function subsetsWithDup(nums: number[]): number[][] {
  nums.sort((a, b) => a - b);
  const res: number[][] = [];
  const path: number[] = [];

function backtrack(start: number) {
    res.push([...path]);
    for (let i = start; i < nums.length; i++) {
      if (i > start && nums[i] === nums[i - 1]) continue;
      path.push(nums[i]);
      backtrack(i + 1);
      path.pop();
    }
  }

backtrack(0);
  return res;
}

/*
function old_subsetsWithDup(nums: number[]): number[][] {
  // older recursive approach kept for reference
  const results: number[][] = [];
  function helper(i: number, current: number[]) {
    if (i === nums.length) {
      results.push(current.slice());
      return;
    }
    helper(i + 1, current);
    current.push(nums[i]);
    helper(i + 1, current);
    current.pop();
  }
  helper(0, []);
  return results;
}
*/

const DEFAULT_LIMIT = 1000000;

class SubsetGenerator {
  private nums: number[];
  private limit: number;

constructor(nums: number[], limit = DEFAULT_LIMIT) {
    this.nums = nums.slice();
    this.limit = limit;
  }

build(): number[][] {
    const out: number[][] = [];
    const stack: number[] = [];

const helper = (index: number) => {
      if (out.length > this.limit) return;
      out.push(stack.slice());
      for (let i = index; i < this.nums.length; i++) {
        stack.push(this.nums[i]);
        helper(i + 1);
        stack.pop();
      }
    };

helper(0);
    return out;
  }

// Potential extension point: filtering duplicates
  private filterDuplicates(sets: number[][]): number[][] {
    const seen = new Set<string>();
    const result: number[][] = [];
    for (const s of sets) {
      const key = s.join(',');
      if (!seen.has(key)) {
        seen.add(key);
        result.push(s);
      }
    }
    return result;
  }
}

function deepCopyMatrix(mat: number[][]): number[][] {
  return mat.map(row => row.slice());
}