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Solving LeetCode - Two Sum

phariale profile image pharia-le ・2 min read

Question

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

You can return the answer in any order.

Example 1:

Input: nums = [2,7,11,15], target = 9
Output: [0,1]
Output: Because nums[0] + nums[1] == 9, we return [0, 1].
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Example 2:

Input: nums = [3,2,4], target = 6
Output: [1,2]
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Example 3:

Input: nums = [3,3], target = 6
Output: [0,1]
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Constraints:

  • 2 <= nums.length <= 105
  • -109 <= nums[i] <= 109
  • -109 <= target <= 109
  • Only one valid answer exists.

Let's Go!

Solve by using PREP.

  • P - Two parameters. First is an array of integers (nums). Second is an integer (target).
  • R - An array of two integers which are the indices of the numbers that add to the target.
  • E - Examples provided by question. (See Above)
  • P - See Below
var twoSum = function(nums, target) {
  // Iterate over nums array with for loop where i is the indice of the first integer
    // Perform a second iteration starting from j where j is the is the indice of the next integer (j=i+1)
      // If nums[i] + nums[j] equals target integer
        // return [i, j] 
}

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Translate into code...

var twoSum = function(nums, target) {
  // Iterate over nums array with for loop where i is the indice of the first element
    for (let i=0; i<nums.length; i++) {
    // Perform a second iteration where j is the is the indice of the second element
        for (let j=i+1; j<nums.length; j++) {
      // If nums[i] + nums[j] equals target integer
        // return [i, j] 
            if (nums[i] +nums[j] === target)
                return [i, j]
        }
    }
}

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Conclusion

& Remember... Happy coding, friends! =)

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