//two sum : 

//Input: nums = [2,7,11,15], target = 9

//Output: [0,1]

//Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].

​

var twoSum = function (nums, target) {

  for (let index in nums) {

    const remaining = target - nums[index]

    const output = nums

    output.splice(index, 1,null)

    if (output.includes(remaining)) {

​

      return [nums.indexOf(remaining), index]

    }

​

  }

}

​

​

​

var twoSum = function(nums, target) {

    let obj = {}

    for(let i = 0; i < nums.length; i++) {

        if (obj.hasOwnProperty(target-nums[i])) {

            return [obj[target-nums[i]], i]

        }

        obj[nums[i]] = i

    }

};

​