Question

/**

 1678. Goal Parser Interpretation

 You own a Goal Parser that can interpret a string command. The command consists of an alphabet of "G", "()" and/or "(al)" in some order. The Goal Parser will interpret "G" as the string "G", "()" as the string "o", and "(al)" as the string "al". The interpreted strings are then concatenated in the original order.

 Given the string command, return the Goal Parser's interpretation of command.


 Example 1:

 Input: command = "G()(al)"
 Output: "Goal"
 Explanation: The Goal Parser interprets the command as follows:
 G -> G
 () -> o
 (al) -> al
 The final concatenated result is "Goal".


 Example 2:

 Input: command = "G()()()()(al)"
 Output: "Gooooal"


 Example 3:

 Input: command = "(al)G(al)()()G"
 Output: "alGalooG"


 Constraints:
     1 <= command.length <= 100
     command consists of "G", "()", and/or "(al)" in some order.
 */

Algorithm

Use a dictionary for checking every input. If match, output related answer.

Or, use regex to replace.

Code

Java

public class Goal_Parser_Interpretation {

    class Solution_regex {
        public String interpret(String command) {
            return command.replaceAll("\\(\\)", "o").replaceAll("\\(al\\)", "al");
        }
    }

    class Solution {
        StringBuilder sb = new StringBuilder();

        public String interpret(String command) {
            dfs(command);

            return sb.toString();
        }

        private void dfs(String command) {
            if (command == null || command.length() == 0) {
                return;
            }

            if (command.substring(0,1).equals("G")) {
                sb.append("G");
                dfs(command.substring(1));
            } else if (command.length() >= 2 && command.substring(0,2).equals("()")) {
                sb.append("o");
                dfs(command.substring(2));
            } else if (command.length() >= 4 && command.substring(0,4).equals("(al)")) {
                sb.append("al");
                dfs(command.substring(4));
            } else {
                sb.append(command.substring(0,4));
                dfs(command.substring(4));
            }
        }
    }
}

Java

  • class Solution {
        public String interpret(String command) {
            command = command.replaceAll("\\(al\\)", "al");
            command = command.replaceAll("\\(\\)", "o");
            return command;
        }
    }
    
  • // OJ: https://leetcode.com/problems/goal-parser-interpretation/
    // Time: O(N)
    // Space: O(1)
    class Solution {
    public:
        string interpret(string s) {
            string ans;
            for (int i = 0; i < s.size(); ) {
                if (s[i] == 'G') ans += 'G', ++i;
                else if (s[i + 1] == ')') ans += 'o', i += 2;
                else ans += "al", i += 4;
            }
            return ans;
        }
    };
    
  • # 1678. Goal Parser Interpretation
    # https://leetcode.com/problems/goal-parser-interpretation/
    
    class Solution:
        def interpret(self, C: str) -> str:
            
            n = len(C)
            i = 0
            res = []
            
            while i < n:
                if C[i] == "G":
                    res.append("G")
                    i += 1
                elif C[i] == "(" and i + 1 < n and C[i+1] == ")":
                    res.append("o")
                    i += 2
                elif C[i] == "(" and i + 3 < n and C[i:i+4] == "(al)":
                    res.append("al")
                    i += 4
                else:
                    i += 1
                
            
            return "".join(res)
                
    

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