844. Backspace String Compare.cpp

// 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 = "#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".
//  

// Constraints:

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

// 来源：力扣（LeetCode）
// 链接：https://leetcode-cn.com/problems/backspace-string-compare
// 著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

class Solution {
public:
    bool backspaceCompare(string s, string t) {
        vector<char> sstack;
        vector<char> tstack;
        for(const auto c:s)
        {
            if(c=='#')
            {
                if(sstack.size()!=0)
                {
                sstack.pop_back();
                }
            }
            else 
            {
                sstack.push_back(c);
            }
        }
        for(const auto c:t)
        {
            if(c=='#')
            {
                if(tstack.size()!=0)
                {
                    tstack.pop_back();
                }
            }
            else {
                tstack.push_back(c);
            }
        }
        return sstack==tstack;
    }
};