RemoveAdjacentDuplicates.md

Problem

Method-1: Stack

class Solution {
    public String removeDuplicates(String s) {
        
        if(s.length()==1)
            return s;
        
        char[] arr = s.toCharArray();
        LinkedList<Character> stack = new LinkedList<Character>();
        stack.push(arr[0]);
        for(int i=1;i<arr.length;i++){
            if(stack.size()>0 && arr[i]==stack.peek()){
                stack.poll();
            }
            else{
                stack.push(arr[i]);
            }
        }
        StringBuilder output = new StringBuilder("");
        for(Character ch : stack){
            output.append(ch);
        }
        return new String(output.reverse());
    }
}

Stack solution of leetcode

public String removeDuplicates(String S) {
    StringBuilder sb = new StringBuilder();
    for (char c : S.toCharArray()) {
        int size = sb.length();
        if (size > 0 && sb.charAt(size - 1) == c) {
            sb.deleteCharAt(size - 1);
        } else {
            sb.append(c);
        }
    }
    return sb.toString();
}

Method-2: Two Pointer

class Solution {
    public String removeDuplicates(String s) {
        
        if(s.length()==1)
            return s;
        
        char[] arr = new char[s.length()];
        int i=-1,j;
        for(j=0;j<s.length();j++){
            if(i>=0 && arr[i]==s.charAt(j)){
                --i;
            } else{
                arr[++i] = s.charAt(j);
            }
        }
        return new String(arr,0,i+1);
    }
}

Best Solution