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Data Structures & Algorithms Interview Questions

Review this list of 271 Data Structures & Algorithms interview questions and answers verified by hiring managers and candidates.
  • "def changeString(org: str,target:str) -> bool: lOrg = len(org) lTarget = len(target) \# They have to be equal in lenght if lOrg != lTarget: return False counter1 = Counter(org) counter2 = Counter(target) \# Counter internally iterates through the input sequence, counts the number of times a given object occurs, and stores objects as keys and the counts as values. if counter1 != counter2: return False diff = sum(org[i] != target[i] for i in range(n)) return diff == 2 or (diff == 0 and any(v > 1 f"

    Rafał P. - "def changeString(org: str,target:str) -> bool: lOrg = len(org) lTarget = len(target) \# They have to be equal in lenght if lOrg != lTarget: return False counter1 = Counter(org) counter2 = Counter(target) \# Counter internally iterates through the input sequence, counts the number of times a given object occurs, and stores objects as keys and the counts as values. if counter1 != counter2: return False diff = sum(org[i] != target[i] for i in range(n)) return diff == 2 or (diff == 0 and any(v > 1 f"See full answer

    Data Structures & Algorithms
    Coding
  • Meta logoAsked at Meta 
    21 answers
    +17

    "function swap(arr, i, j) { const temp = arr[i]; arr[i] = arr[j]; arr[j] = temp; } function sortKMessedArray(arr, k) { for (let i=0; i < arr.length; i++) { for (let j=1; j <= k; j++) { if (arr[i+j] < arr[i]) { swap(arr, i, i+j); } } } return arr; } `"

    Tiago R. - "function swap(arr, i, j) { const temp = arr[i]; arr[i] = arr[j]; arr[j] = temp; } function sortKMessedArray(arr, k) { for (let i=0; i < arr.length; i++) { for (let j=1; j <= k; j++) { if (arr[i+j] < arr[i]) { swap(arr, i, i+j); } } } return arr; } `"See full answer

    Software Engineer
    Data Structures & Algorithms
    +1 more
  • Adobe logoAsked at Adobe 
    16 answers
    +12

    "Problem Statement: The Fibonacci sequence is defined as F(n) = F(n-1) + F(n-2) with F(0) = 1 and F(1) = 1. The solution is given in the problem statement itself. If the value of n = 0, return 1. If the value of n = 1, return 1. Otherwise, return the sum of data at (n - 1) and (n - 2). Explanation: The Fibonacci sequence is a series of numbers where each number is the sum of the two preceding ones, typically starting with 0 and 1. Java Solution: public static int fib(int n"

    Rishi G. - "Problem Statement: The Fibonacci sequence is defined as F(n) = F(n-1) + F(n-2) with F(0) = 1 and F(1) = 1. The solution is given in the problem statement itself. If the value of n = 0, return 1. If the value of n = 1, return 1. Otherwise, return the sum of data at (n - 1) and (n - 2). Explanation: The Fibonacci sequence is a series of numbers where each number is the sum of the two preceding ones, typically starting with 0 and 1. Java Solution: public static int fib(int n"See full answer

    Software Engineer
    Data Structures & Algorithms
    +2 more
  • TikTok logoAsked at TikTok 
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    Video answer for 'Split an array into equal sum subarrays'
    Data Engineer
    Data Structures & Algorithms
    +1 more
  • Meta logoAsked at Meta 
    1 answer

    "Given a Binary Tree, the task is to find its vertical traversal starting from the leftmost level to the rightmost level. If multiple nodes pass through a vertical line, they should be printed as they appear in the level order traversal of the tree. The idea is to traverse the tree using dfs and maintain a hashmap to store nodes at each horizontal distance (HD) from the root. Starting with an HD of 0 at the root, the HD is decremented for left children and incremented for right children. As we"

    Anonymous Mongoose - "Given a Binary Tree, the task is to find its vertical traversal starting from the leftmost level to the rightmost level. If multiple nodes pass through a vertical line, they should be printed as they appear in the level order traversal of the tree. The idea is to traverse the tree using dfs and maintain a hashmap to store nodes at each horizontal distance (HD) from the root. Starting with an HD of 0 at the root, the HD is decremented for left children and incremented for right children. As we"See full answer

    Software Engineer
    Data Structures & Algorithms
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  • Oracle logoAsked at Oracle 
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    Software Engineer
    Data Structures & Algorithms
    +1 more
  • Adobe logoAsked at Adobe 
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    Data Engineer
    Data Structures & Algorithms
    +4 more
  • Apple logoAsked at Apple 
    1 answer

    "We have a list of documents. We want to build an index that maps keywords to documents containing them. Then, given a query keyword, we can efficiently retrieve all matching documents. docs = [ "Python is great for data science", "C++ is a powerful language", "Python supports OOP and functional programming", "Weather today is sunny", "Weather forecast shows rain" ]"

    Mridul J. - "We have a list of documents. We want to build an index that maps keywords to documents containing them. Then, given a query keyword, we can efficiently retrieve all matching documents. docs = [ "Python is great for data science", "C++ is a powerful language", "Python supports OOP and functional programming", "Weather today is sunny", "Weather forecast shows rain" ]"See full answer

    Machine Learning Engineer
    Data Structures & Algorithms
    +1 more
  • Apple logoAsked at Apple 
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    Software Engineer
    Data Structures & Algorithms
    +4 more
  • Amazon logoAsked at Amazon 
    1 answer

    "Count items between indices within compartments compartments are delineated by by: '|' items are identified by: '*' input_inventory = "*||||" inputstartidxs = [1, 4, 6] inputendidxs = [9, 5, 8] expected_output = [3, 0, 1] Explanation: "*||||" 0123456789... indices ++ + # within compartments ^ start_idx = 1 ^ end_idx = 9 -- - # within idxs but not within compartments "*||||" 0123456789... indices "

    Anonymous Unicorn - "Count items between indices within compartments compartments are delineated by by: '|' items are identified by: '*' input_inventory = "*||||" inputstartidxs = [1, 4, 6] inputendidxs = [9, 5, 8] expected_output = [3, 0, 1] Explanation: "*||||" 0123456789... indices ++ + # within compartments ^ start_idx = 1 ^ end_idx = 9 -- - # within idxs but not within compartments "*||||" 0123456789... indices "See full answer

    Software Engineer
    Data Structures & Algorithms
    +1 more
  • "/* You are with your friends in a castle, where there are multiple rooms named after flowers. Some of the rooms contain treasures - we call them the treasure rooms. Each room contains a single instruction that tells you which room to go to next. * instructions1 and treasurerooms_1 * lily* --------- daisy sunflower | | | v v v jasmin --> tulip* violet* ----> rose* --> ^ | ^ ^ | "

    Azeezat R. - "/* You are with your friends in a castle, where there are multiple rooms named after flowers. Some of the rooms contain treasures - we call them the treasure rooms. Each room contains a single instruction that tells you which room to go to next. * instructions1 and treasurerooms_1 * lily* --------- daisy sunflower | | | v v v jasmin --> tulip* violet* ----> rose* --> ^ | ^ ^ | "See full answer

    Software Engineer
    Data Structures & Algorithms
    +1 more
  • Meta logoAsked at Meta 
    1 answer

    "find total sum. assign that to rightsum traverse from left to right: keep updating left sum and right sum, when they match return the index. else if you reach end return -1 or not found"

    Rahul J. - "find total sum. assign that to rightsum traverse from left to right: keep updating left sum and right sum, when they match return the index. else if you reach end return -1 or not found"See full answer

    Software Engineer
    Data Structures & Algorithms
    +1 more
  • 21 answers
    +15

    "import Foundation func spiralCopy(inputMatrix: [[Int]]) -> [Int] { let arr = inputMatrix var top = 0, down = arr.count - 1 var left = 0, right = arr[0].count - 1 if top == down && left == right { return arr[top] } var ans: [Int] = [] while top <= down && left <= right { for i in left..<right { ans.append(arrtop) } for i in top..<down { ans.append(arri) } fo"

    Reno S. - "import Foundation func spiralCopy(inputMatrix: [[Int]]) -> [Int] { let arr = inputMatrix var top = 0, down = arr.count - 1 var left = 0, right = arr[0].count - 1 if top == down && left == right { return arr[top] } var ans: [Int] = [] while top <= down && left <= right { for i in left..<right { ans.append(arrtop) } for i in top..<down { ans.append(arri) } fo"See full answer

    Data Structures & Algorithms
    Coding
  • Meta logoAsked at Meta 
    1 answer

    "Problem: Given an input string txt consisting of alphanumeric characters and the parentheses characters '(' & ')', write a function which removes the minimum number of characters to return a version of the string with properly balanced parenthesis. Answer: You can do this with a counter. Psuedo-Python Start with counter = 0 output = [] Iterate through the string, every time you encounter a '(', increment the counter. Add the character to the output. If you encounter a ')', decrement the coun"

    Michael B. - "Problem: Given an input string txt consisting of alphanumeric characters and the parentheses characters '(' & ')', write a function which removes the minimum number of characters to return a version of the string with properly balanced parenthesis. Answer: You can do this with a counter. Psuedo-Python Start with counter = 0 output = [] Iterate through the string, every time you encounter a '(', increment the counter. Add the character to the output. If you encounter a ')', decrement the coun"See full answer

    Machine Learning Engineer
    Data Structures & Algorithms
    +1 more
  • Google logoAsked at Google 
    2 answers

    "def split_count(s): return 2**(len(s)-1) `"

    Steve M. - "def split_count(s): return 2**(len(s)-1) `"See full answer

    Software Engineer
    Data Structures & Algorithms
    +1 more
  • Adobe logoAsked at Adobe 
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    Software Engineer
    Data Structures & Algorithms
    +4 more
  • Microsoft logoAsked at Microsoft 
    15 answers
    Video answer for 'Find the number of rotations in a circularly sorted array.'
    +10

    "function findRotations(nums) { if (nums.length 0 && nums[mid] > nums[mid-1]) { left = mid; } else { right = mid; } } return rig"

    Tiago R. - "function findRotations(nums) { if (nums.length 0 && nums[mid] > nums[mid-1]) { left = mid; } else { right = mid; } } return rig"See full answer

    Software Engineer
    Data Structures & Algorithms
    +1 more
  • "solving to find a cycle in directed graph"

    XponentShift32 - "solving to find a cycle in directed graph"See full answer

    Backend Engineer
    Data Structures & Algorithms
    +1 more
  • Google logoAsked at Google 
    2 answers

    "Yes, I need to compare the first half of the first string with the reverse order of the second half of the second string. Repeat this process to the first half of the second string and the second half of the first string."

    Anonymous Condor - "Yes, I need to compare the first half of the first string with the reverse order of the second half of the second string. Repeat this process to the first half of the second string and the second half of the first string."See full answer

    Machine Learning Engineer
    Data Structures & Algorithms
    +1 more
  • Meta logoAsked at Meta 
    1 answer

    "Merge Sort"

    Ankita G. - "Merge Sort"See full answer

    Data Engineer
    Data Structures & Algorithms
    +1 more
Showing 101-120 of 271