function removeDuplicates(nums: number[]): number {
    const list = {};
    let total = 0;
    for(let i = 0; i < nums.length; i += 1) {
        if(!list[nums[i]]) {
            list[nums[i]] = true;
            total += 1;
        } else {
            nums.splice(i, 1);
            i -= 1;
        }
    }
    return total;
};