10. Remove all duplicates from a given string

The problem can be found at the following link: Question Link

My Approach.

Simple straightforward questions.

• I use an unordered_set to keep track of characters encountered.

• Iterate through the input string.

• If the current character is not in the set, add it to the output string and insert it into the set.

• Return the output string.

Time and Auxiliary Space Complexity

• Time Complexity : O(N), where N is the length of the input string. We iterate through the string once.

• Auxiliary Space Complexity : O(N), where N is the length of the input string.

Code (C++)

class Solution {
public:
    string removeDuplicates(string str) {
        unordered_set<char> st;
        string out;
        for(auto i : str){
            if(st.find(i) == st.end()){
                out += i;
                st.insert(i);
            }
        }
        return out;
    }
};

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