Master the steps to efficiently track data, solve permutations, anagrams, and game design problems.

Coding

The Knowing What to Track pattern focuses on identifying and maintaining only the key variables or states necessary to solve a problem efficiently, such as counts, indices, or states. It simplifies logic, reduces complexity, and improves efficiency.

Knowing What to Track

Efficiently prepare for coding interviews with strategies from FAANG engineers. Avoid the LeetCode grind and simplify your interview prep with real-world questions from top companies.

The ultimate guide to the System Design Interview – developed by Meta & Google engineers. Master distributed system fundamentals, and practice with real-world interview questions & mock interviews.

System Design

The essential guide to API Design & Product Design Interviews – developed by FAANG engineers. Master product design fundamentals & get hands-on with real-world APIs.

API Design

A battle-tested guide to Object Oriented Design Interviews – developed by FAANG engineers. Master OOD fundamentals & practice real-world interview questions.

Low Level Design Interview Using OOD Principles

Your essential EM Interview crash course. Learn strategies from FAANG hiring managers to demonstrate your leadership skills & experience to interviewers.

Engineering Management and Leadership Interviews

The ultimate guide to behavioral interviews. Developed by FAANG engineers. Use real-world questions, video recording, and structured strategies to get interview-ready in just a few hours.

Behavioral

# Statement

Given a list of strings `strs`, group together all strings that are anagrams of each other.

An anagram is a string formed by rearranging the letters of another string, using all original letters exactly once. For example, "eat", "tea", and "ate" are anagrams.

Return a list of groups, where each group contains strings that are anagrams of each other.
> **Note:** The order of the groups and the order of strings within each group does not matter.

**Constraints:**

Let `strs` be the list of strings given as input to find the anagrams.

- $1 \leq$ `strs.length` $\leq 10^3$
- $0 \leq$ `strs[i].length` $\leq 100$
- `strs[i]` consists of lowercase English letters.

What is the output if the following list is given as input?
 
['bat', 'tab', 'tan', 'at']



What is the output if the following list is given as input?
[‘bat’, ‘tab’, ‘tan’, ‘at’]

[['angel', 'angle', 'egal'],  ['study', 'dusty'], [glean'], ['night', 'thing']]

[['angel', 'glean', 'angle'], ['study', 'dusty'], ['night', 'thing'], ['egal']]

[['angel', 'glean', 'angle', 'egal'], ['study', 'dusty'], ['night', 'thing']]

[['angel', 'glean', 'angle', 'egal'], ['study', 'dusty'], ['night'], ['thing']]

What is the output if the following list is given as input?
 
['angel', 'study', 'glean', 'night', 'angle', 'thing', 'egal', 'dusty']

What is the output if the following list is given as input?
[‘angel’, ‘study’, ‘glean’, ‘night’, ‘angle’, ‘thing’, ‘egal’, ‘dusty’]

[['state', 'taste'], ['save', 'vase'], ['robed', 'bored', 'bore'], ['sat']]

[['state', 'taste', 'sat'], ['save', 'vase'], ['robed', 'bored', 'bore']]

[['state', 'taste', 'sat'], ['save', 'vase'], ['robed', 'bored'], ['bore']]

[['state', 'taste'], ['save', 'vase'], ['robed', 'bored'], ['sat'], ['bore']]

What is the output if the following list is given as input?
 
['state', 'save', 'robed', 'sat', 'taste', 'bored', 'vase', 'bore']

What is the output if the following list is given as input?
[‘state’, ‘save’, ‘robed’, ‘sat’, ‘taste’, ‘bored’, ‘vase’, ‘bore’]

Group Anagrams

Group Anagrams

## Try it yourself

Implement your solution in the following coding playground.

def group_anagrams(strs):

    # Replace this placeholder return statement with your code
    return [[]]


# 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: `group_anagrams`\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 `group_anagrams` 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 `group_anagrams`.\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) `group_anagrams`. \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) `group_anagrams`. \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.

Convert

TwoDArray

import sys
import json

sys.path.append("../ds_v1")
from data_structure import DataStructure

# throw parsing errors for incorrect test case format
def parsingError(element_string, error_message):
    sys.stderr.write(f"Parsing Error: {element_string} {error_message}")
    exit()


# className: MyCustomDS
class Convert(DataStructure):
    def __init__(self):
        # constructor
        pass

    def __str__(self):
        # override print() for your data structure
        pass

    # return value will be passed to user program
    def construct(self, value: str, type_of_arr: int) -> any:
        # parse test case in json string 'value' to your desired data structure
        return value

    # input param contains return value of user program
    def traverse(self, input: any, type_of_arr: int) -> str:
        # convert your data structure 'input' to a json string representing a test case output
        return json.dumps(input)


import sys
import json

sys.path.append("../ds_v1")
from data_structure import DataStructure

# throw parsing errors for incorrect test case format
def parsingError(element_string, error_message):
    sys.stderr.write(f"Parsing Error: {element_string} {error_message}")
    exit()


# className: MyCustomDS
class TwoDArray(DataStructure):
    def __init__(self):
        # constructor
        pass

    def __str__(self):
        # override print() for your data structure
        pass

    # return value will be passed to user program
    def construct(self, value: str, type_of_arr: int) -> any:
        # parse test case in json string 'value' to your desired data structure
        return value

    # input param contains return value of user program
    def traverse(self, input: any, type_of_arr: int) -> str:
        # TwoDArray your data structure 'input' to a json string representing a test case output
        return json.dumps(input)


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
        """
        # 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(group_anagrams_test(self.__inputs[0]))

        if json.dumps(sorted(group_anagrams_test(self.__inputs[0]))) == json.dumps(sorted(self.__actual_outputs[0])):
            self.__edu_result.store_result(expected_outputs, TestCaseResult.PASS)
        else:
            self.__edu_result.store_result(expected_outputs, TestCaseResult.FAIL)

        return self.__edu_result
def dict_to_lst(subset):
        result = []
        if subset == []:
            return [[]]
        for dic in subset:
            result.append(list(dic))
        return result


def group_anagrams_test(strs):
    res = {}  # Hashmap for count
    for s in strs:
        count = [0] * 26  # A place for every single alphabet in our string
        # We will compute the frequency for every string
        for i in s:
            # Calculating the value from 1 to 26 for the alphabet
            index = ord(i) - ord('a')
            count[index] += 1  # Increasing its frequency in the hashmap
        # Each element in this tuple represents the frequency of an
        # English letter in the corresponding title
        key = tuple(count)
        if key in res:
            res[key].append(s)
        else:
            # We add the string as an anagram if it matched the content
            # of our res hashmap
            res[key] = [s]
    return dict_to_lst(res.values())


from group_anagrams import group_anagrams


def group_anagrams_main(strs):
    return list(group_anagrams(strs))


flatten_nested_list_iterator.yaml

testcases:
  - name: "testcase 1"
    inputs:
    - 1 : ["eat","tea","tan","ate","nat","bat"]
    output: 
    - 1 : [["eat", "tea", "ate"], ["bat"], ["tan", "nat"]]
  - name: "testcase 2"
    inputs:
    - 1: ["word", "sword", "drow", "rowd", "iced", "dice"]
    output:
    - 1 : [["word", "drow", "rowd"], ["sword"], ["iced", "dice"]]
  - name: "testcase 3"
    inputs:
    - 1 : ["eat", "drink", "sleep", "repeat"]
    output: 
    - 1 : [["eat"], ["drink"], ["sleep"], ["repeat"]]
  - name: "testcase 4"
    inputs:
    - 1: ["hello", "ohlle", "dark"]
    output:
    - 1 : [["hello", "ohlle"], ["dark"]]
  - name: "testcase 5"
    inputs:
    - 1: ["eat", "beat", "neat", "tea"]
    output:
    - 1 : [["eat", "tea"], ["beat"], ["neat"]]

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

def validate_inputs(self) -> None:
 """
 Validate the list of strings (strs) based on the given constraints.
 Store the result using self.store_result(error_msg, status).
 return: void
 """
 strs = self.__inputs[0]

 if not (1 <= len(strs) <= 10**3):
 self.store_result("Number of strings in 'strs' should be in the range 1 <= strs.length <= 10^3", ValidationFunction.FAIL)
 return

 for s in strs:
 if not (0 <= len(s) <= 100):
 self.store_result("String length in strs should be in the range 0 <= strs[i].length <= 100", ValidationFunction.FAIL)
 return

 elif not all(char.islower() for char in s):
 self.store_result("Each string in strs should consist of only lowercase English letters", ValidationFunction.FAIL)
 return

 self.store_result("", ValidationFunction.PASS)

Problem: Group Anagrams

Statement

Examples

Understand the problem

Figure it out!