feat(leetcode/medium/251-flatten-2d-vector.py)·

coding-challange/leetcode/medium/251-flatten-2d-vector/251-flatten-2d-vector.py

@@ -0,0 +1,38 @@
+"""
+251-flatten-2d-vector
+leetcode/medium/251. Flatten 2D Vector
+Difficulty: medium
+URL: https://leetcode.com/problems/flatten-2d-vector/
+"""
+
+from typing import List
+
+
+class Vector2D:
+    def flattening(self, _list, _result):
+        for item in _list:
+            if not isinstance(item, list):
+                _result.append(item)
+            else:
+                self.flattening(item, _result)
+
+    def __init__(self, vec: List[List[int]]):
+        self._list = []
+        self.flattening(vec, self._list)
+
+    def next(self) -> int:
+        return self._list.pop(0)
+
+    def hasNext(self) -> bool:
+        return len(self._list) > 0
+
+
+def test():
+    vector2D = Vector2D([[1, 2], [3], [4]])
+    assert vector2D.next() == 1
+    assert vector2D.next() == 2
+    assert vector2D.next() == 3
+    assert vector2D.hasNext() == True
+    assert vector2D.hasNext() == True
+    assert vector2D.next() == 4
+    assert vector2D.hasNext() == False