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Behavioral

Given two non-negative integers, `str1` and `str2`, represented as strings, return the product of these integers, `result`, which is also represented as strings.

**Constraints:**
- `str1` and `str2` consist of digits only.
- $1 \leq$ `str1.length`, `str2.length`  $\leq 200$
- No leading $0$ in `str1` or `str2` 

Given the following two strings, what will be the answer?

str1 = "3"

str2 = "6"

Given the following two strings, what will be the answer?
str1 = “3”
str2 = “6”

Given the following two strings, what will be the answer?

str1 = "5"

str2 = "4"

Given the following two strings, what will be the answer?
str1 = “5”
str2 = “4”

Given the following two strings, what will be the answer?

str1 = "100"

str2 = "121"

Given the following two strings, what will be the answer?
str1 = “100”
str2 = “121”

Multiply Strings

Multiply Strings

# Quick Fix\nYou are Edward, a Senior Software Engineer who specializes in coding interview patterns, data structures and algorithms, and is great at debugging issues in code.\n\n- Edward, please keep in mind that you do not have to print the data of the placeholders. Also, do not mention anything about yourself.\n\nEdward, you are given the following data in the placeholders:\n- Function name: `multiply_strings`\n- Candidate's submitted solution code: USER_CODE\n- Error: ERROR_DESCRIPTION\n- Failed test case: FAILED_TEST_CASE\n- Coding language: `Python`\n\n- Edward, your task is to understand the type of error that is occurring in the coding language provided.\n- Once you've understood the error as per the error’s description, and why the test case failed, you will suggest how the candidate can improve their solution code to fix the error.\n- Edward, you will not give the corrected code, just a hint on what the error tells, and how to fix it.\n- Edward, please limit your response strictly to 100 words. No more words than the limit.

# Review Code\nEdward, your current task is to review the `multiply_strings` function(s) and the other function(s) invoked in it/them.\n\n-Take your time and review the candidate's solution code.\n- Do not review any extra/helper files or functions not invoked in the solution function `multiply_strings`.\n- Do not review the code of data structure 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. \n- Also, if the solution code doesn’t use the coding pattern stated above, then please encourage the candidate to reattempt the problem using that pattern corectly.

# Review time complexity\n- Please provide a brief time complexity analysis of the function(s) `multiply_strings`. \n- While calculating time complexity, include the time complexity of built-in Python functions invoked by the code. \n- The answer should be to the point in approximately 60 words.

# Review space complexity\n- Please provide a brief space complexity analysis of the function(s) `multiply_strings`. \n- While calculating space complexity, include the space complexity of built-in Python functions invoked by the code. \n- 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). \n- The answer should be to the point in approximately 60 words.

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 multiply_strings(str1, str2):
	        if "0" in [str1, str2]:
		        return "0"
	        result = [0] * (len(str1) + len(str2))
	        str1, str2 = str1[::-1], str2[::-1]

	        for i in range(len(str1)):
		        for j in range(len(str2)):
			        ans = int(str1[i]) * int(str2[j])
			        ans += result[i + j]
			        result[i + j + 1] += (ans // 10)
			        result[i + j] = ans % 10
	
	        if result[-1] == 0:
		        result.pop()
	        result = result[::-1]

	        result = map(str, result)
	        return "".join(result)
        
        expected_outputs = [] 
        expected = multiply_strings(self.__inputs[0], self.__inputs[1])
        actual_output = self.__actual_outputs[0]
        

        if expected == actual_output:
            expected_outputs.append(expected)
            self.__edu_result.store_result(expected_outputs, TestCaseResult.PASS)
        else:
            expected_outputs.append(expected)
            self.__edu_result.store_result(expected_outputs, TestCaseResult.FAIL)

        return self.__edu_result

def multiply_strings(str1, str2):
    
    # Replace this placeholder return statement with your code
    return "-1"

multiply_strings.yaml

testcases:
  - name: "testcase 1"
    inputs:
    - 1 : "20"
    - 2 : "5"
    output: 
    - 1 : "100"
  - name: "testcase 2"
    inputs:
    - 1: "100"
    - 2: "100"
    output:
    - 1 : "10000"
  - name: "testcase 3"
    inputs:
    - 1: "135"
    - 2: "246"
    output:
    - 1 : "33210"
  - name: "testcase 4"
    inputs:
    - 1: "10101"
    - 2: "10111"
    output:
    - 1 : "102131211"
  - name: "testcase 5"
    inputs:
    - 1: "30000"
    - 2: "2005"
    output:
    - 1 : "60150000"

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
 """

 def starts_with_zero(input_string):
 return input_string[0] == '0' if input_string else False
 
 str1 = self.__inputs[0]
 str2 = self.__inputs[1]

 if not (1 <= len(str1) <= 200):
 self.store_result ("expected 'str1' to have " + str(1) + " <= size <= " + str(200) + " but got " + str(len(str1)) , ValidationFunction.FAIL)
 elif not (1 <= len(str2) <= 200):
 self.store_result ("expected 'str2' to have " + str(1) + " <= size <= " + str(200) + " but got " + str(len(str2)) , ValidationFunction.FAIL)
 elif starts_with_zero(str1) == True and len(str1)!=1:
 self.store_result ("'str1' should not contain leading 0s", ValidationFunction.FAIL)
 elif starts_with_zero(str2) == True and len(str2)!=1:
 self.store_result ("'str2' should not contain leading 0s", ValidationFunction.FAIL)
 elif str1.isdigit() == False:
 self.store_result ("'str1' should contain only digits", ValidationFunction.FAIL)
 elif str2.isdigit() == False:
 self.store_result ("'str2' should contain only digits", ValidationFunction.FAIL)
 else:
 self.store_result("", ValidationFunction.PASS)

Try to solve the Multiply Strings problem.

Problem: Multiply Strings

Statement

Examples

Understand the problem

Figure it out!