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Four number sum question

Holy answered on October 17, 2023 Popularity 3/10 Helpfulness 1/10

answer Four number sum question

Four number sum question

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function fourNumberSum(array, targetSum) {
  // Sort the input array in ascending order.
  array.sort((a, b) => a - b);

  // Initialize an empty array to store the result.
  const result = [];
  // Get the length of the array for efficiency.
  const n = array.length;

  // Iterate through the array from the first element to the third-to-last element.
  for (let i = 0; i < n - 3; i++) {
    // Skip duplicates for the first element to avoid duplicate sets.
    if (i > 0 && array[i] === array[i - 1]) continue;

    // Iterate through the array from the second element to the second-to-last element.
    for (let j = i + 1; j < n - 2; j++) {
      // Skip duplicates for the second element to avoid duplicate sets.
      if (j > i + 1 && array[j] === array[j - 1]) continue;

      // Initialize two pointers for the remaining elements.
      let left = j + 1;
      let right = n - 1;

      // Use a two-pointer approach to find pairs of elements that sum to the target.
      while (left < right) {
        const currentSum = array[i] + array[j] + array[left] + array[right];

        if (currentSum === targetSum) {
          // If a set is found, add it to the result.
          result.push([array[i], array[j], array[left], array[right]]);

          // Skip duplicates for the third and fourth elements.
          while (left < right && array[left] === array[left + 1]) left++;
          while (left < right && array[right] === array[right - 1]) right--;

          // Move the pointers to explore other potential solutions.
          left++;
          right--;
        } else if (currentSum < targetSum) {
          // If the sum is too small, move the left pointer to increase the sum.
          left++;
        } else {
          // If the sum is too large, move the right pointer to decrease the sum.
          right--;
        }
      }
    }
  }

  // Return the resulting array of sets that sum to the target.
  return result;
}

// Do not edit the line below.
exports.fourNumberSum = fourNumberSum;

Popularity 3/10 Helpfulness 1/10 Language javascript

Source: chat.openai.com

Tags: javascript sum

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Contributed on Oct 17 2023

Holy

0 Answers Avg Quality 2/10

Four number sum question

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