LeetCode #844 Backspace字串比較

public class Solution {
    public bool BackspaceCompare(string s, string t) {
        
        string s2 = "";
        int cnt = 0;

        foreach(var a in s){
            if(a == '#'){
                if(cnt>0){
                    cnt-=1;
                    s2 = s2.Substring(0,cnt);
                }

            } else{
                s2 = s2+a;
                cnt+=1;
            }
        }


        string t2 = "";
        cnt = 0;

        foreach(var a in t){
            if(a == '#'){
                if(cnt>0){
                    cnt-=1;
                    t2 = t2.Substring(0,cnt);
                }

            } else{
                t2 = t2+a;
                cnt+=1;
            }
        }
        return s2 == t2;
    }
}

public class Solution {
    public bool BackspaceCompare(string s, string t) {
       return BackspaceString(s) == BackspaceString(t);
    }

    private string BackspaceString(string input) {
        var result = new StringBuilder();
        int cnt = 0;    

        foreach (char c in input) {
            if (c == '#') {
                if (cnt > 0) {
                    result.Length--;
                    cnt--;
                }
            } else {
                result.Append(c);
                cnt++;
            }
        }

        return result.ToString();
    }
}

class Solution {
    public boolean backspaceCompare(String s, String t) {
        return backspaceString(s).equals(backspaceString(t));
    }

    private String backspaceString(String input) {
        StringBuilder result = new StringBuilder();

        for (char c : input.toCharArray()) {
            if (c == '#') {
                if (result.length() > 0) {
                    result.setLength(result.length() - 1);
                }
            } else {
                result.append(c);
            }
        }

        return result.toString();
    }
}

class Solution:
    def backspaceString(self,input):
        result = []
        
        for c in input:
            if c == '#':
                if result:
                    result.pop()
            else:
                result.append(c)
        
        return ''.join(result)

    def backspaceCompare(self, s: str, t: str) -> bool:
        return self.backspaceString(s) == self.backspaceString(t)

/**
 * @param {string} s
 * @param {string} t
 * @return {boolean}
 */
var backspaceCompare = function(s, t) {
    return backspaceString(s) == backspaceString(t);
};


function backspaceString(input){
    let result = '';

    for (let i = 0; i < input.length; i++) {
        if (input[i] === '#') {
            if (result.length > 0) {
                result = result.slice(0, -1);
            }
        } else {
            result += input[i];
        }
    }

    return result;
}