Clear Digits

Leetcode Problem:

• Clear Digits

Summary

• Remove all digits from a given string by deleting the first digit and the closest non-digit character to its left.

Approach

• Use a stack to store the non-digit characters and then join them into a string to get the final result.

Complexity

• O(n) where n is the length of the string

Explain

• The solution iterates through the string and pushes non-digit characters into the stack
• When a digit is encountered, it pops the top element from the stack
• Finally, it joins the characters in the stack into a string and returns it.

Solution Code:

class Solution {
public:
    vector st;
    string clearDigits(string s) {
        for(int i = 0 ; i < s.size(); i++){
            if(s[i] >= 'a' && s[i] <= 'z'){
                st.push_back(s[i]);
            }else{
                if(st.size() != 0){
                    st.pop_back();
                }
            }
        }
        string res = "";
        for(int i = 0 ; i < st.size(); i++){
            res += st[i];
        }
        return res;
    }
};