Code Review (Warmup): Tautological (Useless) Comments

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Code Review (Warmup): Tautological (Useless) Comments

Story

i++ // increment i

Yes. We can see that.

Comments that repeat the code add noise, not clarity.

Worse, they teach readers to ignore comments, which is a problem when a comment actually does matter.

Rule of thumb:

If the code already says it, the comment shouldn't.

function fourSum(nums: number[], target: number): number[][] { // declare function fourSum with parameters nums and target
  const n = nums.length; // set n to the length of nums
  const res: number[][] = []; // initialize res as an empty array of number arrays
  if (n < 4) return res; // if there are fewer than 4 numbers return res
  nums.sort((a, b) => a - b); // sort nums in ascending order

for (let i = 0; i < n - 3; i++) { // loop i from 0 to n-4 inclusive
    if (i > 0 && nums[i] === nums[i - 1]) continue; // skip this i if it's the same as previous
    const min1 = nums[i] + nums[i + 1] + nums[i + 2] + nums[i + 3]; // compute the minimum possible sum with nums[i]
    if (min1 > target) break; // break the outer loop if min1 exceeds target
    const max1 = nums[i] + nums[n - 1] + nums[n - 2] + nums[n - 3]; // compute the maximum possible sum with nums[i]
    if (max1 < target) continue; // continue to next i if max1 is less than target

for (let j = i + 1; j < n - 2; j++) { // loop j from i+1 to n-3 inclusive
      if (j > i + 1 && nums[j] === nums[j - 1]) continue; // skip this j if it's the same as previous j
      const min2 = nums[i] + nums[j] + nums[j + 1] + nums[j + 2]; // compute the minimum possible sum with nums[i] and nums[j]
      if (min2 > target) break; // break the j-loop if min2 exceeds target
      const max2 = nums[i] + nums[j] + nums[n - 1] + nums[n - 2]; // compute the maximum possible sum with nums[i] and nums[j]
      if (max2 < target) continue; // continue to next j if max2 is less than target

return res; // return the resulting array of quadruplets
}

export default fourSum; // export fourSum as the default export

function fourSum(nums: number[], target: number): number[][] {
  const n = nums.length;
  const res: number[][] = [];
  if (n < 4) return res;
  nums.sort((a, b) => a - b);

for (let i = 0; i < n - 3; i++) {
    if (i > 0 && nums[i] === nums[i - 1]) continue;
    const min1 = nums[i] + nums[i + 1] + nums[i + 2] + nums[i + 3];
    if (min1 > target) break;
    const max1 = nums[i] + nums[n - 1] + nums[n - 2] + nums[n - 3];
    if (max1 < target) continue;

for (let j = i + 1; j < n - 2; j++) {
      if (j > i + 1 && nums[j] === nums[j - 1]) continue;
      const min2 = nums[i] + nums[j] + nums[j + 1] + nums[j + 2];
      if (min2 > target) break;
      const max2 = nums[i] + nums[j] + nums[n - 1] + nums[n - 2];
      if (max2 < target) continue;

return res;
}

export default fourSum;