Flatten a Nested Python Structure (lists/dicts/tuples) into a List of Integers

Problem: Flatten a Nested Structure When working with hierarchical data, you may need to convert a nested structure into a flat list. Input Given a nested Python-like data structure structure whose nodes can be: list tuple dict Constraint: all leaf nodes (innermost values) are guaranteed to be integers (int). Output Return a 1D list flat_list containing all integers from structure in traversal order. Traversal / Ordering Rules For list / tuple: traverse elements from left to right. For dict: traverse its values following the dictionary’s iteration order of keys (Python insertion/iteration order). Example Input: {'a': [1, 2, 3], 'b': {'c': [{'d': 4}], 'e': 5}} Output: [1, 2, 3, 4, 5] Constraints Nesting depth D: 1 ≤ D ≤ 10^4 Number of leaf integers N: 1 ≤ N ≤ 2 * 10^5 Requirements Must handle very deep nesting correctly. Target time complexity: O(N), where N is the number of leaf integers. Example Input {'a': [1, 2, 3], 'b': {'c': [{'d': 4}], 'e': 5}} Output [1, 2, 3, 4, 5]