function insertionSort(arr) {
    for (let i = 1; i < arr.length; i++) {
        let j = i - 1;
        while (j >= 0 && arr[j+1] < arr[j]) {
            let tmp = arr[j + 1];
            arr[j + 1] = arr[j];
            arr[j] = tmp;
            j--;
        }
    }
    return arr;
}