index.js

// Given two strings S and T, return 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 = "#a#c"
// Output: true
// Explanation: Both S and T become "c".

//     Example 4:

// Input: S = "a#c", T = "b"
// Output: false
// Explanation: S becomes "c" while T becomes "b".
//     Note:

// 1 <= S.length <= 200
// 1 <= 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 ?

// Solution

const backspaceCompare = (S, T) => {
    return process(S) === process(T);
};

const process = (str) => {
    const stack = [];
    for (let char of str) {
        char === '#' ? stack.pop() : stack.push(char);
    }
    return stack.join('');
}