# LC 3174. Clear Digits

### [Problem link](https://leetcode.com/problems/clear-digits/)

###### tags: `leedcode` `easy` `c++`

You are given a string <code>s</code>.

Your task is to remove **all** digits by doing this operation repeatedly:

- Delete the first digit and the **closest** **non-digit** character to its left.

Return the resulting string after removing all digits.

**Example 1:**
Input: s = "abc"

Output: "abc"

Explanation:

There is no digit in the string.

**Example 2:**
Input: s = "cb34"

Output: ""

Explanation:

First, we apply the operation on <code>s[2]</code>, and <code>s</code> becomes <code>"c4"</code>.

Then we apply the operation on <code>s[1]</code>, and <code>s</code> becomes <code>""</code>.

**Constraints:**

- <code>1 <= s.length <= 100</code>
- <code>s</code> consists only of lowercase English letters and digits.
- The input is generated such that it is possible to delete all digits.

## Solution 1
#### C++

class Solution {
public:
    string clearDigits(string s) {
        vector<char> st;
        for (char& c: s) {
            if (st.size() > 0 && isdigit(c)) {
                st.pop_back();
            } else {
                st.push_back(c);
            }
        }
        string res(st.begin(), st.end());
        return res;
    }
};

>### Complexity
>| | Time Complexity | Space Complexity |
>| ----------- | --------------- | ---------------- |
>| Solution 1 | O(n) | O(n) |

## Note
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