Javascript:Leet Code -Find pair of number in array whose sum equal to target

Find a pair of number from array whose sum is equal to target

nums = [2, 7, 11, 15]

target = 9

function targetSumPair(nums, target) {

    arr = []

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

        for (let j = i + 1; j < nums.length; j++) {

            if(nums[i]>target && nums[j] > target) continue

            if (nums[i] + nums[j] == target) {

                return [i, j]

            } else {

                console.log(`i=${nums[i]} j=${nums[j]}`)

            }

        }

    }

}

console.log(targetSumPair(nums,target))

Expected Optimized Way:

function targetSumPair(nums, target) {

    let obj = {};

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

        let complement = target - nums[i];

        if (obj[complement] !== undefined) {

            return [obj[complement], i];

        }

        obj[nums[i]] = i;

    }

}

console.log(targetSumPair([2, 7, 11, 15], 9));{

 

Javascript:Array insert between the array

Here 16 is missing between 9 & 25 that we need to insert at that very place.

let arr = [1, 4, 9, 25, 36];

arr.splice(3, 0, 16);

console.log(arr);

Output:

    [1, 4, 9, 16, 25, 36]

splice(3, 0, 16) means:

3 → index where to insert

0 → don't remove anything if 1 remove one element,if 2 remove 2 element

16 → value to insert 

Here  Original array is mutated.

let arr = [1, 4, 9, 25, 36];

arr.splice(3, 0, 16,17,18);

console.log(arr);

Output:

   [

   1,  4,  9, 16,

  17, 18, 25, 36

]

splice(3, 0, 16) //means:

3 → index where to insert

0 → don't remove anything if 1 remove one element,if 2 remove 2 element

 16,17,18 → value to insert