LeetCode-in-Java

3174. Clear Digits

Easy

You are given a string s.

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 s[2], and s becomes "c4".

Then we apply the operation on s[1], and s becomes "".

Constraints:

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

Solution

public class Solution {
    public String clearDigits(String s) {
        StringBuilder result = new StringBuilder();
        for (char ch : s.toCharArray()) {
            if (ch >= '0' && ch <= '9') {
                if (!result.isEmpty()) {
                    result.deleteCharAt(result.length() - 1);
                }
            } else {
                result.append(ch);
            }
        }
        return String.valueOf(result);
    }
}

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