Remove All Adjacent In String 2

RemoveAllAdjacentInString2.java

//https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string-ii/description/
class Solution {
    public String removeDuplicates(String s, int k) {
        Deque<Character> stack = new ArrayDeque<>();
        Deque<Integer> nums = new ArrayDeque<>();
        stack.push('#');        nums.push(1);
        int n = s.length();
        for(int i=0;i<n;i++){
            if(s.charAt(i) == stack.peek()){
                nums.push(nums.peek()+1);
            }
            else{
                nums.push(1);
            }
            stack.push(s.charAt(i));
            if(nums.peek()==k)      popKtimes(nums, stack, k);
        }
        StringBuilder sb = new StringBuilder();
        while(stack.size()>1)       sb.append(stack.pop());
        sb.reverse();
        return sb.toString();
    }
    public void popKtimes(Deque<Integer> nums, Deque<Character> stack, int k){
        int c = 0;
        while(c<k){
            nums.pop();     stack.pop();        c++;
        }
    }
}