Problem
This is the advanced follow-up to Flatten a 2D Array. Practice that challenge first. Here lists may contain more lists at any depth. In C++ and C#, use the NestedValue type in the starter code. Read kind first: 0 means skip this entry, 1 means append value, and 2 means visit items recursively.
Turn a nested list into a flat list of integers. Read from left to right; whenever you reach another list, read its contents before continuing. Ignore null values (shown as None in examples) and empty lists. Preserve repeated integers and their order.
Python receives ordinary nested lists containing integers and None. C++ and C# receive a list of NestedValue objects supplied by the starter: kind 0 means null, kind 1 means integer in value, and kind 2 means a list in items. Only the field selected by kind matters. Return a plain integer list in every language.
Implement flatten_arbitrarily_nested_list(values).
Input
values: A list whose entries can be integers, null, or further lists.
Output
Return the integers in depth-first, left-to-right order. Return an empty list when there are no integers.
Einschränkungen
The outer value is a list. At most 10,000 entries across all lists; maximum nesting depth 50. Integer leaves fit signed 64-bit. Leaves are integers or null, never strings or booleans.
Beispiele
Eingabe:
values = [
1,
[
2,
None,
[3]
],
[],
4
]
Erwartete Ausgabe:
expected = [1, 2, 3, 4]Verwende den Typ NestedValue aus dem Startcode. Die Felder sind kind (0 = null, 1 = Integer, 2 = Liste), value (der Integer) und items (die verschachtelte Liste).
Eingabe:
std::vector<NestedValue> values = {
NestedValue{1, 1, {}},
NestedValue{2, 0, {
NestedValue{1, 2, {}},
NestedValue{0, 0, {}},
NestedValue{2, 0, {
NestedValue{1, 3, {}}
}}
}},
NestedValue{2, 0, {}},
NestedValue{1, 4, {}}
};
Erwartete Ausgabe:
std::vector<long long> expected = {1, 2, 3, 4};Verwende den Typ NestedValue aus dem Startcode. Die Felder sind kind (0 = null, 1 = Integer, 2 = Liste), value (der Integer) und items (die verschachtelte Liste).
Eingabe:
NestedValue[] values = new NestedValue[] {
new NestedValue { kind = 1, value = 1 },
new NestedValue { kind = 2, items = new NestedValue[] {
new NestedValue { kind = 1, value = 2 },
new NestedValue { kind = 0 },
new NestedValue { kind = 2, items = new NestedValue[] {
new NestedValue { kind = 1, value = 3 }
} }
} },
new NestedValue { kind = 2, items = new NestedValue[] {} },
new NestedValue { kind = 1, value = 4 }
};
Erwartete Ausgabe:
long[] expected = new long[] {1, 2, 3, 4};Erläuterung
Read 1, then enter the nested list and read 2 and 3, skipping null. The empty list adds nothing; finish with 4.
Eingabe:
values = [
None,
[],
[None]
]
Erwartete Ausgabe:
expected = []Verwende den Typ NestedValue aus dem Startcode. Die Felder sind kind (0 = null, 1 = Integer, 2 = Liste), value (der Integer) und items (die verschachtelte Liste).
Eingabe:
std::vector<NestedValue> values = {
NestedValue{0, 0, {}},
NestedValue{2, 0, {}},
NestedValue{2, 0, {
NestedValue{0, 0, {}}
}}
};
Erwartete Ausgabe:
std::vector<long long> expected = {};Verwende den Typ NestedValue aus dem Startcode. Die Felder sind kind (0 = null, 1 = Integer, 2 = Liste), value (der Integer) und items (die verschachtelte Liste).
Eingabe:
NestedValue[] values = new NestedValue[] {
new NestedValue { kind = 0 },
new NestedValue { kind = 2, items = new NestedValue[] {} },
new NestedValue { kind = 2, items = new NestedValue[] {
new NestedValue { kind = 0 }
} }
};
Erwartete Ausgabe:
long[] expected = new long[] {};Erläuterung
Every entry is null or an empty container. No integer remains.
Referenzen
Diese Aufgabe wurde für CodeUtility angepasst. Beachte die oben genannten Vorgaben und Einschränkungen.