Find count of pairs of HackerRank code challenge

find-pairs.js

const ar = [10, 20, 20, 10, 10, 30, 50, 10, 20];

const getPairs = (n, ar) => {
    let pairs = 0, i = 0;
    ar.sort((a, b) => a - b);

    while (i < n) {

        const count = ar.filter(item => item === ar[i]).length;
        if (count >= 2) {
            i = i + count;
            const divide = (count / 2);
            pairs += Math.floor(divide);

        } else {
            i += 1;
        }

    }
    return pairs;
}

const getPairsSecond = (n, ar) => {
    let pairs = 0;
    let foundedNum = [];
    for (let i = 0; i < n; i++) {
        let count = 0;
        for (let j = 0; j < n; j++) {

            if (ar[i] == ar[j] && foundedNum.indexOf(ar[j]) == -1) {
                count++;                            
            }
        }
        if (count >= 2){    
            const divide = (count / 2);
            pairs += Math.floor(divide);
            foundedNum.push(ar[i]);
        }
    }
    return pairs;
}

console.time("FIRST");
console.log(getPairs(ar.length, ar));
console.timeEnd("FIRST");

console.time("SECOND");
console.log(getPairsSecond(ar.length, ar));
console.timeEnd("SECOND");