3447. Clear Digits

难度: Easy

题目描述

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.

Note that the operation cannot be performed on a digit that does not have any non-digit character to its left.

 

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.

解题思路

代码实现

解决方案

java

class Solution {
    public String clearDigits(String s) {

        LinkedList<Character> stack = new LinkedList<>();
        char[] charArray = s.toCharArray();
        LinkedList<Character> temp = new LinkedList<>();
        for (int i = s.length() - 1; i > -1; i--) {
            if (charArray[i] >= '0' && charArray[i] <= '9') {
                stack.push(charArray[i]);
            } else {
                if (stack.isEmpty()) {
                    stack.push(charArray[i]);
                    continue;
                } else {

                    boolean flag = false;
                    while (!stack.isEmpty()) {
                        char pc = stack.peek();
                        if (pc >= '0' && pc <= '9') {
                            stack.pop();
                            flag = true;
                            break;
                        }
                        temp.push(stack.pop());
                    }
                    while (!temp.isEmpty()) {
                        stack.push(temp.pop());
                    }
                    if (!flag) {
                        stack.push(charArray[i]);
                    }
                }
            }
        }
        StringBuilder sb = new StringBuilder();
        while (!stack.isEmpty()) {
            sb.append(stack.pop());
        }
        return sb.toString();

    }
}