我在面试中被问到这个问题
Given a hypothetical list in java that, along with holding integer content, may also hold another list of similar type
示例:[1,3,5,[6,7],8,9,10,[11,13,15,[16,17,[18,19]]],20]
输出应该是:
[1,3,5,6,7,8,9,10,11,13,15,16,17,18,19,20]
我觉得很简单!所以我想出了一个解决问题的递归解决方案!还是不行?
面试官说子列表可以深入到任何深度,因此可能会导致 stackoverflow 错误!
我尝试想出一个非递归的解决方案,但做不到。谁能说出非递归解决方案可能是什么?
最佳答案
您可以将 LinkedList 用作堆栈。
public static List<Object> flattenNonRecursive(List<Object> list) {
List<Object> result = new ArrayList<>();
LinkedList<Object> stack = new LinkedList<>(list);
while (!stack.isEmpty()) {
Object e = stack.pop();
if (e instanceof List<?>)
stack.addAll(0, (List<?>)e);
else
result.add(e);
}
return result;
}
public static List<Object> list(Object... args) {
return Arrays.asList(args);
}
public static void main(String[] args) {
List<Object> list = list(1, 3, 5, list(6, 7), 8, 9, 10, list(11, 13, 15, list(16, 17, list(18, 19))), 20);
System.out.println("flatten=" + flattenNonRecursive(list));
}
结果
flatten=[1, 3, 5, 6, 7, 8, 9, 10, 11, 13, 15, 16, 17, 18, 19, 20]
关于java - 在 Java 中展平列表,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/30950677/