removeAllMatchingInts.js

function solution(myArr) {
    var myArr = [9, 3, 9, 3, 9, 7, 9, 4, 5, 6, 8, 3, 4, 1, 2, 5, 6, 7, 7, 4, 2];
    var sortedArray = myArr.slice().sort();
    var pairedArray = [];
    var leftUnpaired = [];

    console.log(sortedArray);
    var i;
    for (i = 0; i < sortedArray.length - 1; i++) {
        if (sortedArray[i + 1] == sortedArray[i] || sortedArray[i - 1] == sortedArray[i]) {
            pairedArray.push(sortedArray[i]);
        } else if (sortedArray[i + 1] != sortedArray[i]) {
            leftUnpaired.push(sortedArray[i])
        }
    }
    console.log(pairedArray);
    console.log(leftUnpaired);

}
solution();