Learn and practice the Hash Maps and Knowing What to Track patterns to solve coding interview problems.

Educative-77 in JavaScript: Accelerate Your Coding Interview Prep

Hash maps are powerful data structures that enable programmers to design more efficient solutions for certain problems. After practicing solving problems using hash maps, we will move to the more general problem-solving skill of figuring out the key characteristics of a problem, using various techniques to track them, in order to design remarkably efficient solutions for seemingly complex problems.

Hashing and Tracking

* Both the strings consist of valid ASCII characters.
* The length of the string is $0$ $\leq$ `length` $\leq$ $10^{4}$.

* The length of both strings is the same. 


## Understand the problem

Let's take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check that you’re solving the correct problem:

What is the output, if the following strings are given as an input?

string1 = "ACAB"

string2 = "XCXY"


What is the output, if the following strings are given as an input?
string1 = “ACAB”
string2 = “XCXY”

What is the output, if the following strings are given as an input?

string1 = "aab"

string2 = "xyz"



What is the output, if the following strings are given as an input?
string1 = “aab”
string2 = “xyz”

What is the output, if the following strings are given as an input?

string1 = "awz"

string2 = "xwz"



What is the output, if the following strings are given as an input?
string1 = “awz”
string2 = “xwz”

What is the output, if the following strings are given as an input?

string1 = "AAAA"

string2 = "AAAA"



What is the output, if the following strings are given as an input?
string1 = “AAAA”
string2 = “AAAA”

Isomorphic strings

Isomorphic strings

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Implement your solution in the following coding playground.

Help me debug only the function(s) `isIsomorphic`. I don't need the corrected code, just some hints on how to use the "Hash Maps" pattern to solve this problem. I don't want explanations. Just provide me with the exact error that helps me run the code successfully on the test cases provided.

Please help me understand why this code failed for the provided failed test case. Don't give me the corrected code. Just some hints on how to use the "Hash Maps" pattern to improve my solution or fix the error. First, check whether the given pattern is used or not. If yes, then Just provide me the exact error that helps me run the code successfully on the test cases provided.

Your current task is to review only the `isIsomorphic` function(s) and the other function(s) invoked in it/them. Do not review extra/helper files or functions not invoked in the solution function `isIsomorphic`. Do not review the code of data structures objects instantiated like a binary tree, linked list, trie, union find, etc., in the solution functions. Just review the solution/algorithm function of the problem. Also, answer the following questions: Is the "Hash Maps" pattern used? Take your time and review the code.

Please provide a brief time complexity analysis of the function(s) `isIsomorphic`. While calculating time complexity, include the time complexity of built-in JavaScript functions invoked by the code. The answer should be to the point and in a few lines.

Please provide a brief space complexity analysis of the function(s) `isIsomorphic`. While calculating space complexity, include the space complexity of built-in JavaScript functions invoked by the code. Do not include the space used for the input parameters and the space used for just returning an output(not used as a scratch space). The answer should be to the point and in a few lines.

def evaluate_results(self) -> object:
        """
        self.__inputs is the list of inputs that are passed as input to function
        self.__actual_output is a list of outputs that is produced by the learner's code
        return : self.__edu__result object
        """
        def is_isomorphic(string1, string2):
            map_str1_str2 = {}
            map_str2_str1 = {}

            for i in range(len(string1)):
                char1 = string1[i]
                char2 = string2[i]

                if char1 in map_str1_str2 and map_str1_str2[char1] != char2:
                    return False

                if char2 in map_str2_str1 and map_str2_str1[char2] != char1:
                    return False

                map_str1_str2[char1] = char2
                map_str2_str1[char2] = char1

            return True
        
        # Expected output
        expected = is_isomorphic(self.__inputs[0], self.__inputs[1])

        # Actual output
        actual = self.__actual_outputs[0]

        # multiple outputs will be added at each index respectively for a single test_case
        expected_outputs = [] 

        # store the 1st expected output that should be displayed to the user 
        expected_outputs.append(expected)

        if json.dumps(expected) == json.dumps(actual):
            self.__edu_result.store_result(expected_outputs, TestCaseResult.PASS)
        else:
            self.__edu_result.store_result(expected_outputs, TestCaseResult.FAIL)

        return self.__edu_result

export function isIsomorphic(string1, string2){

    // Replace this placeholder return statement with your code
    return false
}


PrivateTestCases.yaml

testcases:
  - name: "testcase 1"
    inputs:
    - 1 : egg
    - 2 : all
    output: 
    - 1 : True
  - name: "testcase 2"
    inputs:
    - 1: foo
    - 2: bar
    output:
    - 1 : False
  - name: "testcase 3"
    inputs:
    - 1: paper
    - 2: title
    output:
    - 1: True
  - name: "testcase 4"
    inputs:
    - 1: badc
    - 2: baba
    output:
    - 1: False
  - name: "testcase 5"
    inputs:
    - 1: aaeaa
    - 2: uuxyy
    output:
    - 1: False

def sum(input_1, input_2):
    return input_1+input_2

def validate_inputs(self) -> None:
 """
 self.__inputs is the list of inputs that are passed as input to function
 store the result using the self.store_result(error_msg, status)
 return : void
 """
 import string
 
 def are_valid_characters(s):
 for char in s:
 if char not in string.printable:
 return False
 return True
 
 string1 = self.__inputs[0]
 string2 = self.__inputs[1]

 string1_length = len(string1)
 string2_length = len(string2)

 strings_lower_bound = 0
 strings_upper_bound = 5 * (10**4)
 
 # inputs can be accessed using self.__inputs starting from 0 to len(self.__inputs) - 1
 if not are_valid_characters(string1):
 self.store_result ("\"" + string1 + "\"" + " is not a valid value of type string", ValidationFunction.FAIL)

 elif not are_valid_characters(string2):
 self.store_result ("\"" + string2 + "\"" + " is not a valid value of type string", ValidationFunction.FAIL)

 elif string1_length > strings_upper_bound:
 self.store_result ("expected 'string1' to have " + str(strings_lower_bound) + " <= size <= " + str(strings_upper_bound) + " but got " + str(string1_length), ValidationFunction.FAIL)

 elif string1_length != string2_length:
 self.store_result("expected 'string2' to have " + str(string1_length) + " <= size <= " + str(string1_length) + " but got " + str(string2_length), ValidationFunction.FAIL)

 else:
 self.store_result("", ValidationFunction.PASS)

Try to solve the Isomorphic Strings problem.


Isomorphic Strings

Try to solve the Isomorphic Strings problem.

Hash Maps

Knowing What to Track

Conclusion

Isomorphic Strings

Statement

Examples

Understand the problem

Figure it out!

Try it yourself