LeetCode-341. 扁平化嵌套列表迭代器

给定一个嵌套的整型列表。设计一个迭代器，使其能够遍历这个整型列表中的所有整数。

列表中的项或者为一个整数，或者是另一个列表。

示例 1:

输入: [[1,1],2,[1,1]]
输出: [1,1,2,1,1]
解释: 通过重复调用 next 直到 hasNext 返回false，next 返回的元素的顺序应该是: [1,1,2,1,1]。
示例 2:

输入: [1,[4,[6]]]
输出: [1,4,6]
解释: 通过重复调用 next 直到 hasNext 返回false，next 返回的元素的顺序应该是: [1,4,6]。

简单题，递归展开就行。

/**
 * // 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;
 * };
 */


#include <iostream>
#include <vector>
#include <queue>
using namespace std;

class NestedIterator {
public:
    NestedIterator(vector<NestedInteger> &nestedList) {
        noWind(nestedList);
    }
    int next() {
        int res = m_queue.front();
        m_queue.pop();
        return res;
    }

    bool hasNext() {
        return !m_queue.empty();
    }

    void noWind(vector<NestedInteger> &nest) {
        for(int i=0;i<nest.size();i++){
            if(nest[i].isInteger()){
                m_queue.push(nest[i].getInteger());
            }else{
                vector<NestedInteger> son = nest[i].getList();
                noWind(son);
            }
        }
    }

private:
    queue<int> m_queue;     /* 设置队列 */

};

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