844. Backspace String Compare

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題目敘述

Given two strings s and t, return true if they are equal when both are typed into empty text editors. '#' means a backspace character.

Note that after backspacing an empty text, the text will continue empty.

Example 1

Input: s = “ab#c”, t = “ad#c” Output: true Explanation: Both s and t become “ac”.

Example 2

Input: s = “ab##”, t = “c#d#” Output: true Explanation: Both s and t become “”.

Example 3

Input: s = “a#c”, t = “b” Output: false Explanation: s becomes “c” while t becomes “b”.

解題思路

Solution

import java.util.Stack;

class Solution {
    public boolean backspaceCompare(String s, String t) {
        Stack<Character> stackS = new Stack<>();
        Stack<Character> stackT = new Stack<>();

        for(int i = 0; i < s.length(); i++){
            if(s.charAt(i) == '#'){
                if(stackS.size() != 0)
                    stackS.pop();
            }else{
                stackS.push(s.charAt(i));
            }
        }

        for(int i = 0; i < t.length(); i++){
            if(t.charAt(i) == '#'){
                if(stackT.size() != 0)
                    stackT.pop();
            }else{
                stackT.push(t.charAt(i));
            }
        }

        if(stackS.size() != stackT.size()){
            return false;
        }

        String compareS = stackS.toString();
        String compareT = stackT.toString();

        return compareS.equals(compareT);
    }
}