1. Write an algorithm that takes an array and moves all of the zeros to the end, preserving the order of the other elements.

// input: [false,1,0,1,2,0,1,3,"a"]
// output: [false,1,1,2,1,3,"a",0,0]

var moveZeros = function (arr) {
  return [
    ...(arr.filter(n => n !== 0)),
    ...(arr.filter(n => n === 0))
  ];
}

2. Find all pairs in an array of integers whose sum is equal to a given number.

// input: array=[2,3,12,3,5,0,8,23,-1,2]; sum=5
// output:  [2, 3],[2, 3],[3, 2],[3, 2], 5, 0]

function findPairsWithSum(arr, S) {
 const sum = [];
  for(let i = 0; i< arr.length; i++) {
    for(let j = i+1;  j < arr.length; j++) {
      if(S == arr[i] + arr[j]) sum.push([arr[i],arr[j]])
    }
  }
 return sum
}