Flatten Nested List Iterator

最新推荐文章于 2022-05-08 19:51:35 发布

phlovexz

最新推荐文章于 2022-05-08 19:51:35 发布

阅读量302

点赞数

CC 4.0 BY-SA版权

分类专栏： LeetCode 文章标签： c语言

本文链接：https://blog.youkuaiyun.com/u013609078/article/details/51669148

LeetCode 专栏收录该内容

109 篇文章

订阅专栏

本文介绍了一种用于处理嵌套整数列表的数据结构——嵌套迭代器，并分别用C++与Python实现。该迭代器可以平滑地遍历包含多个层级的整数列表，提供next和hasNext等方法，简化了复杂嵌套数据结构的处理过程。

c++

/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * class NestedInteger {
 *   public:
 *     // Return true if this NestedInteger holds a single integer, rather than a nested list.
 *     bool isInteger() const;
 *
 *     // Return the single integer that this NestedInteger holds, if it holds a single integer
 *     // The result is undefined if this NestedInteger holds a nested list
 *     int getInteger() const;
 *
 *     // Return the nested list that this NestedInteger holds, if it holds a nested list
 *     // The result is undefined if this NestedInteger holds a single integer
 *     const vector<NestedInteger> &getList() const;
 * };
 */
class NestedIterator {
public:
    NestedIterator(vector<NestedInteger> &nestedList) {
        iterator(nestedList);
    }

    int next() {
        int res = cache.front();
        cache.pop();
        return res;
    }

    bool hasNext() {
        return !cache.empty();
    }
private:
    queue<int> cache;

    void iterator(const vector<NestedInteger> &List) {
        for (auto &v : List) {
            if (v.isInteger())
                cache.push(v.getInteger());
            else {
                iterator(v.getList());
            }
        }
    }
};

/**
 * Your NestedIterator object will be instantiated and called as such:
 * NestedIterator i(nestedList);
 * while (i.hasNext()) cout << i.next();
 */

python

class NestedIterator(object):

    def __init__(self, nestedList):
        """
        Initialize your data structure here.
        :type nestedList: List[NestedInteger]
        """
        self.cache = collections.deque() 
        self.iterator(nestedList)
    def next(self):
        """
        :rtype: int
        """
        return self.cache.popleft()

    def hasNext(self):
        """
        :rtype: bool
        """
        return True if len(self.cache)>0 else False

    def iterator(self, nestlist):
        for v in nestlist:
            if v.isInteger():
                self.cache.append(v.getInteger())
            else:
                self.iterator(v.getList())