34-Make-The-String-Great.md

Make The String Great

Problem Link

https://leetcode.com/problems/make-the-string-great/

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Pattern

• Stack
• String

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Approach

Use a stack to remove adjacent characters that are the same letter but different case.

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Time Complexity

O(n)

Space Complexity

O(n)

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Java Solution

import java.util.*;
class Solution {
    public String makeGood(String s) {
        Stack<Character> stack = new Stack<>();
        for (char c : s.toCharArray()) {
            if (!stack.isEmpty() && Math.abs(stack.peek() - c) == 32) stack.pop();
            else stack.push(c);
        }
        StringBuilder ans = new StringBuilder();
        for (char c : stack) ans.append(c);
        return ans.toString();
    }
}