LeetCode 284 窥探迭代器[迭代器 构造类] HERODING的LeetCode之路

Posted 2021-10-23 HERODING23

解题思路：
本质是继承 Iterator 类用来实现一个新的 Iterator 只不过多了一个peek，那么就很好解决了，next() 函数和 hasNext() 函数直接返回原来的 Iterator 的函数， peek() 函数用一个指针指向当前的位置，然后返回该指针的next即可，代码如下：

/*
 * Below is the interface for Iterator, which is already defined for you.
 * **DO NOT** modify the interface for Iterator.
 *
 *  class Iterator {
 *		struct Data;
 * 		Data* data;
 *  public:
 *		Iterator(const vector<int>& nums);
 * 		Iterator(const Iterator& iter);
 *
 * 		// Returns the next element in the iteration.
 *		int next();
 *
 *		// Returns true if the iteration has more elements.
 *		bool hasNext() const;
 *	};
 */

class PeekingIterator : public Iterator {
public:
	PeekingIterator(const vector<int>& nums) : Iterator(nums) {
	    // Initialize any member here.
	    // **DO NOT** save a copy of nums and manipulate it directly.
	    // You should only use the Iterator interface methods.
	    
	}
	
    // Returns the next element in the iteration without advancing the iterator.
	int peek() {
        auto temp = *this;
        return temp.next();
	}
	
	// hasNext() and next() should behave the same as in the Iterator interface.
	// Override them if needed.
	int next() {
	    return Iterator :: next();
	}
	
	bool hasNext() const {
	    return Iterator :: hasNext();
	}
};