C#•14mo ago

❔ Only one testcase failed

I am stuck with this puzzle https://leetcode.com/problems/decode-string/submissions/ My code fails at this specific testcase as per screenshot. Could anyone kindly point me in the right direction?

public class DecodeString
{
    public string StringDecode(string s)
    {
        var stkChar = new Stack<char>();
        var stkDigit = new Stack<int>();
        int count = 0;
        string recorded = "";
        string currStr = "";

        for (int i = 0; i < s.Length; i++)
        {
            if (Char.IsDigit(s[i]))
            {
                
                count = count * 10 + s[i] - '0';
                Console.WriteLine($"it is a digit, report me {count}");
            } else if (s[i] == '[')
            {
                stkChar.Push(s[i]); 
                stkDigit.Push(count); 
                count = 0;
                Console.WriteLine("please keep me " + currStr);
                recorded = currStr;
                currStr = "";
                Console.WriteLine($"currStr after opening bracket {currStr}");
            } else if (s[i] == ']')
            {
                
                int poppedCount = stkDigit.Pop();
                //char poppedChar = stkChar.Pop(); 
                string decoded = currStr;
                for (int j = 1; j < poppedCount; j++)
                {
                    decoded += currStr;
                }
                Console.WriteLine($"what is decoded {decoded}");
                currStr = decoded; // Update currStr
                Console.WriteLine($"currStr after closing bracket {currStr}");
                
                
            }
            else
            {
                currStr += s[i];
               
            }
        }

        
        return recorded + currStr;

    }
}

public class DecodeString
{
    public string StringDecode(string s)
    {
        var stkChar = new Stack<char>();
        var stkDigit = new Stack<int>();
        int count = 0;
        string recorded = "";
        string currStr = "";

        for (int i = 0; i < s.Length; i++)
        {
            if (Char.IsDigit(s[i]))
            {
                
                count = count * 10 + s[i] - '0';
                Console.WriteLine($"it is a digit, report me {count}");
            } else if (s[i] == '[')
            {
                stkChar.Push(s[i]); 
                stkDigit.Push(count); 
                count = 0;
                Console.WriteLine("please keep me " + currStr);
                recorded = currStr;
                currStr = "";
                Console.WriteLine($"currStr after opening bracket {currStr}");
            } else if (s[i] == ']')
            {
                
                int poppedCount = stkDigit.Pop();
                //char poppedChar = stkChar.Pop(); 
                string decoded = currStr;
                for (int j = 1; j < poppedCount; j++)
                {
                    decoded += currStr;
                }
                Console.WriteLine($"what is decoded {decoded}");
                currStr = decoded; // Update currStr
                Console.WriteLine($"currStr after closing bracket {currStr}");
                
                
            }
            else
            {
                currStr += s[i];
               
            }
        }

        
        return recorded + currStr;

    }
}

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3 Replies

JakenVeina•14mo ago

so, you're just supposed to be parsing that input commandbas a set of instructions for generating the output? I very much like that I'm not seeing recusrion I'm going to recommend you model the problem a little more at the expense of having an "efficient" solution which is really how you should do most development: implement sensibly first, then optimize where you can so if we think about how to "model" this your input consists of a string, that contains a set of instructions write me a class that represents one of those instructions or a set of classes, if that makes more sense

Moods•14mo ago

ended up doing it out of curiosity; took me longer than id like to admit. if this helps here is my approach and im able to explain any part you have questions about(also sorry Jaken I HAD to use recursion i am not thinking of a solution without one)

public class Solution {

    private HashSet<int> hashset;

    public string DecodeString(string s) 
    {
        hashset = new HashSet<int>();

        var res = Helper(0, s);
   
        return res;
    }

    private string Helper(int start, string str)
    {
        var _res = new StringBuilder();

        for(int a = start; a < str.Length; a++)
        {
            if(str[a] == ']' && !hashset.Contains(a))
            {
                hashset.Add(a);
                break;
            }

            if(Char.IsLetter(str[a]) && !hashset.Contains(a))
            {
                hashset.Add(a);
                _res.Append(str[a]);
            }
            else{
                if(Char.IsNumber(str[a]) && !hashset.Contains(a))
                {
                    string _num = "";
                    while(str[a] != '[')
                    {
                        _num += str[a];
                        hashset.Add(a);
                        a++;
                    }
                    a--;
                    int num = Int32.Parse(_num);
                    string temp = Helper(a + 2, str);

                    string new_temp = Solver(num, temp);

                    _res.Append(new_temp);
                }
            }
        }
        return _res.ToString();
    }

    private string Solver(int count, string sentence)
    {
        string res = "";

        for(int a = 0; a < count; a++)
            res += sentence;

        return res;
    }
}

public class Solution {

    private HashSet<int> hashset;

    public string DecodeString(string s) 
    {
        hashset = new HashSet<int>();

        var res = Helper(0, s);
   
        return res;
    }

    private string Helper(int start, string str)
    {
        var _res = new StringBuilder();

        for(int a = start; a < str.Length; a++)
        {
            if(str[a] == ']' && !hashset.Contains(a))
            {
                hashset.Add(a);
                break;
            }

            if(Char.IsLetter(str[a]) && !hashset.Contains(a))
            {
                hashset.Add(a);
                _res.Append(str[a]);
            }
            else{
                if(Char.IsNumber(str[a]) && !hashset.Contains(a))
                {
                    string _num = "";
                    while(str[a] != '[')
                    {
                        _num += str[a];
                        hashset.Add(a);
                        a++;
                    }
                    a--;
                    int num = Int32.Parse(_num);
                    string temp = Helper(a + 2, str);

                    string new_temp = Solver(num, temp);

                    _res.Append(new_temp);
                }
            }
        }
        return _res.ToString();
    }

    private string Solver(int count, string sentence)
    {
        string res = "";

        for(int a = 0; a < count; a++)
            res += sentence;

        return res;
    }
}

i feel you can do this with a stack though, as that was my initial thought, but i cant be arsed to think of the logic

Accord•14mo ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ Only one testcase failed