Javascript:In one dimesional numeric array find pairs of zero sum element

Problem Statement:

For given one dimensional array of numbers find pair of elements whose sum is zero.

e.g.

if array is

[-4, -10, -8, -3, 3, 4, 5, -5, 7, 8, -7]

then solution should be

[[-4,4],[-8,8],[-3,3],[5,-5],[7,-7]]

Solution (Way 1):

function findPairsWithSumZero(arr) {

var result = [];

//sort

arr = arr.sort((a, b) => {

return a - b;

});

let left = 0;

let right = arr.length - 1;

while (left < right) {

let sum = arr[left] + arr[right];

if (sum == 0) {

result.push([arr[left], arr[right]]);

left++;

right--;

} else if (sum < 0) {

left++;

} else {

right--;

}

}

return result;

}

const myarr = [-4, -10, -8, -3, 3, 4, 5, -5, 7, 8, -7];

const result = findPairsWithSumZero(myarr);

console.log(result);

Output:

[ [ -8, 8 ], [ -7, 7 ], [ -5, 5 ], [ -4, 4 ], [ -3, 3 ] ]

Solution (Way 2):

function findPairsWithSumZero(arr) {

var result = [];

//sort

arr = arr.sort((a, b) => {

return a - b;

});

//loop

for (let i = 0; i < arr.length - 1; i++) {

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

if (arr[i] + arr[j] == 0) {

result.push([arr[i], arr[j]]);

}

}

}

return result;

}

const myarr = [-4, -10, -8, -3, 3, 4, 5, -5, 7, 8, -7];

const result = findPairsWithSumZero(myarr);

console.log(result);

Output:

[ [ -8, 8 ], [ -7, 7 ], [ -5, 5 ], [ -4, 4 ], [ -3, 3 ] ]

Solution (Way 3):

function findPairsWithSumZero(arr) {

const seenNumbers = new Set();

const pairs = [];

for (const num of arr) {

const complement = -num;

if (seenNumbers.has(complement)) {

pairs.push([num, complement]);

}

seenNumbers.add(num);

}

return pairs;

}

const myarr = [-4, -10, -8, -3, 3, 4, 5, -5, 7, 8, -7];

const result = findPairsWithSumZero(myarr);

console.log(result);

Output:

[ [ 3, -3 ], [ 4, -4 ], [ -5, 5 ], [ 8, -8 ], [ -7, 7 ] ]