[JS] Backspace String Compare

🔒 문제 (LeetCode 844)

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.

Constraints:

• 1 <= s.length, t.length <= 200
• s and t only contain lowercase letters and '#' characters.

Follow up: Can you solve it in O(n) time and O(1) space?

 

🌊 입출력

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".

 

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🔑 해결

🌌 알고리즘 - 스택

/**
 * @param {string} s
 * @param {string} t
 * @return {boolean}
 */
var backspaceCompare = function(s, t) {
    const [stack1, stack2] = [[], []];
    
    const makeString = (stack, str) => {
        for(let i = 0; i < str.length; i++) {
            if(str[i] !== '#') stack.push(str[i]);
            else if(stack.length && str[i] === '#') stack.pop();
        }
        
        return stack.join();
    }
    
    return makeString(stack1, s) === makeString(stack2, t)
};