K&R / C library

• atoi.py (easy, arrays)
• itoa.py (easy, arrays)
• squeeze.py (easy, arrays)

Interactive Python

• word_ladder.py (hard, graphs, bfs)
• knight_tour.py (hard, graphs, dfs)

Programming Pearls

• largest_contiguous_subvector.py (moderate/hard, arrays, dynamic programming)

Codility

• equi_index.py (easy, arrays)
• tape_equilibrium.py (easy, arrays)
• prefix_set.py (easy, arrays)
• asymmetry_index.py (moderate) - need to fix
• disc_intersections.py (moderate/hard, arrays, binary search)
• base_neg2.py (moderate/hard)

CodeEval

• fizzbuzz.py (easy)
• multiples.py (easy)
• number_of_ones.py (easy/moderate, bits)
• lowest_common_ancestor.py (easy/moderate, bst)
• wines.py (easy/moderate)
• pass_triangle.py (moderate)
• pascal_triangle.py (moderate)
• digit_stats.py (hard, division)

Pramp

• lover_letter.py (easy, hash tables)
• different_number.py (easy, arrays, hashing)
• duplicates.py (easy, searching, arrays, binary search)
• largest_smaller.py (easy/moderate, bst)
• quad_combination.py (easy/moderate, searching, arrays, hash tables)
• successor_search.py (easy/moderate, bst)
• inorder.py (moderate, bst)
• smallest_substring.py (moderate/hard, searching, strings)
• budget_cuts.py (hard, arrays, binary search)

Cracking the Coding Interview

• replace_spaces.py (easy, arrays)
• string_compression.py (easy, arrays, strings)
• remove_dups.py (easy, linked lists)
• kth_to_last.py (easy, linked lists, recursion)
• remove_middle_node.py (easy, linked lists)

Geeks For Geeks

• rotate_matrix.py (easy/moderate, matrix)
• closest_pair.py (easy/moderate, searching, arrays, mergesort)
• closest_pair2.py (easy/moderate, searching, arrays, mergesort)
• closest_trio.py (easy/moderate, searching, arrays, mergesort)
• nearest_smaller.py (moderate, searching, arrays, stacks)
• pivot_index.py (moderate, searching, arrays)
• url_shortener.py (moderate, arrays, division)
• digits_sum.py (moderate, dynamic programming)
• edit_distance.py (moderate, dynamic programming)
• rod_cut.py (moderate, dynamic programming)
• tree_views.py (moderate)
• level_order.py, vertical_order.py (moderate)

Toptal

• even_numbers.py (easy)

https://github.com/juchem/prep

• count_words.py (easy, strings)
• k_modes.py (moderate, hash tables, arrays, min-heaps)
• interval_overlaps.py (moderate, arrays, mergesort)
• division.py (moderate/hard, recursion, bits)

Miscellaneous

• reconstruct_serialized_tree.py (easy, hash tables)
• square_root.py (easy, binary search)
• fib.py (easy, dynamic programming)
• tree_to_linked_list.py (moderate, bst, linked lists, stacks)
• first_nonrepeat_char.py (moderate/hard, arrays, hash tables, linked lists)
• itertools_recipes.py (not an exercise, stolen from python docs)
• conway_game_of_life.py
• coin_change.py (moderate, dynamic programming)
• longest_substring.py (moderate/hard, searching, strings)
• anagrams.py (moderate/hard, strings)
• longest_ascending.py (hard, arrays, binary search)