Given an array arr of integers, check if there exists two Input
var checkIfExist = function(arr) {
for(let i=0;i<arr.length;i++){
let target = arr[i]
for(let j=i+1;j<arr.length;j++){
if(target === arr[j]*2 || target === arr[j]/2){
return true
}
}
}
return false
};