Two Sum

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
const twoSum = function (nums, target) {
  /**
   * remain value is the final value of target and array's individual element subtraction.
   * If remain Value is present in the given nums array that means we have our answer
   * start and current represents the index value of subtracted number and current number against which comparision is happening in loop;
   * result is to store final result and retuen it ;
   */
  let start = 0;
  let remain = target - nums[start];
  let current = 1;
  let result = [];

  /**
   * WHY NOT FOR LOOP?
   * For loop will only run for limited number of time based on the emenent size in the array, but here i need to loop against every index to compare it with remain value
   * and update remain value till the last element , while is more suitable for such problems where we don't have any predefined iteration count. while loop totally depends
   * on base condition
   */


  /**
   * This condition will make sure we consider all the array elements as substration value.
   */
  while (start <= nums.length - 1) {
    // O(n)  - NOt sure here!!!
    if (remain === nums[current]) {
      if (start !== current) {
        result = [start, current];
        console.log(result);
        break;
      }
    }
    if (current === nums.length - 1) {
    /**
     * I increment current value on every iteration and start value once in loop single phase.
     * after one loop cycle assign current to 0 index again ;
     */
      current = 0;
      start++;
      remain = target - nums[start];
    }
    current++;
  }
  return result;
};

twoSum([3, 2, 4], 6);