Backend Engineer Skills Assessment submission for Rohit Lunavara

.gitignore

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+__pycache__/

container_utils.py

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+"""
+Author: Rohit Lunavara
+Date: 02/16/2021
+"""
+
+SEPARATOR = "/"
+
+def flatten(container):
+    """
+    Accepts a multi-dimensional container of any size and converts it into a one dimensional associative array whose keys are strings representing their value's path in the original container.
+
+    E.g.
+
+    Input:
+    flatten([
+        {
+            "one": 1
+        },
+        {
+            "two": {
+                "three": 3
+            }
+        },
+        {
+            "four": [4, 5, {"five": [6]}]
+        }
+    ])
+
+    Output:
+    {
+        "0/one": 1,
+        "1/two/three": 3,
+        "2/four/0": 4,
+        "2/four/1": 5,
+        "2/four/2/five/0": 6
+    }
+    """
+    if len(container) == 0:
+        return {}
+
+    flattened_container = {}
+    def recursive_flatten(container, current_key = None):
+        # Default list argument results in shared list object between function calls, therefore, we initialize it separately
+        if current_key is None:
+            current_key = []
+
+        if isinstance(container, dict):
+            for key, value in container.items():
+                recursive_flatten(value, current_key + [key])
+
+        elif isinstance(container, list):
+            for index, value in enumerate(container):
+                recursive_flatten(value, current_key + [f"{index}"])
+
+        else:
+            string_key = SEPARATOR.join(current_key)
+            flattened_container[string_key] = container
+
+    recursive_flatten(container)
+    return flattened_container
+
+def widen(container):
+    """
+    Accepts a one dimensional associative array whose keys are strings representing their value's path in a multi-dimensional container and converts it into the original container based on the value's path.
+
+    E.g.
+
+    Input:
+    widen({
+        "0/one": 1,
+        "1/two/three": 3,
+        "2/four/0": 4,
+        "2/four/1": 5,
+        "2/four/2/five/0": 6
+    })
+
+    Output:
+    [
+        {
+            "one": 1
+        },
+        {
+            "two": {
+                "three": 3
+            }
+        },
+        {
+            "four": [4, 5, {"five": [6]}]
+        }
+    ]
+    """
+    def recursive_replacement(container):
+        """
+        Recursively replaces dictionaries containing integer keys in string format with lists.
+        Handles cases where there could be multiple nested dictionaries and lists.
+        """
+        if not isinstance(container, dict):
+            return container
+
+        any_random_key = next(iter(container))
+
+        if isinstance(any_random_key, int):
+            list_size = int(max(container)) + 1
+            list_container = [None] * (list_size)
+
+            for key, value in container.items():
+                list_index = int(key)
+                list_container[list_index] = recursive_replacement(value)
+
+            return list_container
+
+        else:
+            for key, value in container.items():
+                container[key] = recursive_replacement(value)
+
+            return container
+
+    if len(container) == 0:
+        return container
+
+    widened_container = {}
+    # Store lists as dictionaries with integer keys, replace recursively later
+    for key, value in container.items():
+        current_keys = key.split(SEPARATOR)
+        previous_container, current_container = None, widened_container
+
+        for key in current_keys:
+            modified_key = int(key) if key.isdigit() else key
+
+            if modified_key not in current_container:
+                current_container[modified_key] = {}
+
+            previous_container, current_container = current_container, current_container[modified_key]
+
+        previous_container[modified_key] = value
+
+    return recursive_replacement(widened_container)
+
+if __name__ == "__main__":
+    # Test Cases
+    widened_containers = [
+        {
+            "one": 1
+        },
+        {
+            'one':
+            {
+                'two': 3,
+                'four': [5, 6, 7]
+            },
+            'eight':
+            {
+                'nine':
+                {
+                    'ten': 11
+                }
+            }
+        },
+        [
+            {
+                "one": 1
+            },
+                {
+                "two": {
+                    "three": 3
+                }
+            },
+            {
+                "four": [4, 5, {"five": [6]}]
+            }
+        ],
+    ]
+    flattened_containers = [
+        {
+            "one": 1
+        },
+        {
+            'one/two': 3,
+            'one/four/0': 5,
+            'one/four/1': 6,
+            'one/four/2': 7,
+            'eight/nine/ten': 11
+        },
+        {
+            '0/one': 1,
+            '1/two/three': 3,
+            '2/four/0': 4,
+            '2/four/1': 5,
+            '2/four/2/five/0': 6
+        },
+    ]
+
+    for index in range(len(widened_containers)):
+        assert flatten(widened_containers[index]) == flattened_containers[index]
+        assert widen(flattened_containers[index]) == widened_containers[index]
+
+    assert flatten([]) == {}
+    assert flatten({}) == {}
+    assert widen([]) == []
+    assert widen({}) == {}