Practice Backtracking Questions for DSA Coding Interviews

21. Generate Balanced Binary Strings

Required Input:

n = 2

Expected Output:

['1100', '1010']

Code In Python

def generate_balanced_binary(n): # Write your logic here pass # Prefilled input n = 2 print(generate_balanced_binary(n))

Run Code?

Click Run Button to view compiled output

22. Restore IP Addresses

Required Input:

s = '25525511135'

Expected Output:

['255.255.11.135', '255.255.111.35']

Code In Python

def restore_ip_addresses(s): # Write your logic here pass # Prefilled input s = '25525511135' print(restore_ip_addresses(s))

Run Code?

Click Run Button to view compiled output

23. Combinations of k Numbers

Required Input:

n = 4, k = 2

Expected Output:

[[1, 2], [1, 3], [1, 4], [2, 3], [2, 4], [3, 4]]

Code In Python

def combine(n, k): # Write your logic here pass # Prefilled input n = 4 k = 2 print(combine(n, k))

Run Code?

Click Run Button to view compiled output

24. Partition Array into k Equal Sum Subsets

Required Input:

nums = [4, 3, 2, 3, 5, 2, 1], k = 4

Expected Output:

True

Code In Python

def can_partition_k_subsets(nums, k): # Write your logic here pass # Prefilled input nums = [4, 3, 2, 3, 5, 2, 1] k = 4 print(can_partition_k_subsets(nums, k))

Run Code?

Click Run Button to view compiled output

25. Distinct Character Substrings

Required Input:

s = 'abc'

Expected Output:

['a', 'b', 'c', 'bc', 'ab', 'c', 'abc', 'b', 'c', 'bc', 'c']

Code In Python

def distinct_substrings(s): # Write your logic here pass # Prefilled input s = 'abc' print(distinct_substrings(s))

Run Code?

Click Run Button to view compiled output

26. Word Search in Grid

Required Input:

board = [[...]], word = 'ABCCED'

Expected Output:

True

Code In Python

def exist(board, word): # Write your logic here pass # Prefilled input board = [ ['A', 'B', 'C', 'E'], ['S', 'F', 'C', 'S'], ['A', 'D', 'E', 'E'] ] word = 'ABCCED' print(exist(board, word))

Run Code?

Click Run Button to view compiled output

27. Palindrome Partitioning

Required Input:

s = 'aab'

Expected Output:

[['a', 'a', 'b'], ['aa', 'b']]

Code In Python

def partition(s): # Write your logic here pass # Prefilled input s = 'aab' print(partition(s))

Run Code?

Click Run Button to view compiled output

28. Subsets With Duplicates

Required Input:

nums = [1, 2, 2]

Expected Output:

[[], [1], [1, 2], [1, 2, 2], [2], [2, 2]]

Code In Python

def subsets_with_dup(nums): # Write your logic here pass # Prefilled input nums = [1, 2, 2] print(subsets_with_dup(nums))

Run Code?

Click Run Button to view compiled output

29. Unique Paths in Grid

Required Input:

m = 3, n = 2

Expected Output:

Code In Python

def unique_paths(m, n): # Write your logic here pass # Prefilled input m = 3 n = 2 print(unique_paths(m, n))

Run Code?

Click Run Button to view compiled output

30. Sudoku Solver

Required Input:

board = [[...]]

Expected Output:

[
['5', '3', '4', '6', '7', '8', '9', '1', '2'],
['6', '7', '2', '1', '9', '5', '3', '4', '8'],
['1', '9', '8', '3', '4', '2', '5', '6', '7'],
['8', '5', '9', '7', '6', '1', '4', '2', '3'],
['4', '2', '6', '8', '5', '3', '7', '9', '1'],
['7', '1', '3', '9', '2', '4', '8', '5', '6'],
['9', '6', '1', '5', '3', '7', '2', '8', '4'],
['2', '8', '7', '4', '1', '9', '6', '3', '5'],
['3', '4', '5', '2', '8', '6', '1', '7', '9']
]

Code In Python

def solve_sudoku(board): # Write your logic here pass # Prefilled input board = [ ['5','3','.','.','7','.','.','.','.'], ['6','.','.','1','9','5','.','.','.'], ['.','9','8','.','.','.','.','6','.'], ['8','.','.','.','6','.','.','.','3'], ['4','.','.','8','.','3','.','.','1'], ['7','.','.','.','2','.','.','.','6'], ['.','6','.','.','.','.','2','8','.'], ['.','.','.','4','1','9','.','.','5'], ['.','.','.','.','8','.','.','7','9'] ] solve_sudoku(board) print(board)

Run Code?

Click Run Button to view compiled output

3 of 3