oj350. Intersection of Two Arrays II
来源:互联网 发布:阿里云快速备案' 编辑:程序博客网 时间:2024/05/16 01:31
Given two arrays, write a function to compute their intersection.
Example:
Given nums1 = [1, 2, 2, 1]
, nums2 = [2, 2]
, return [2, 2]
.
Note:
- Each element in the result should appear as many times as it shows in both arrays.
- The result can be in any order.
Follow up:
- What if the given array is already sorted? How would you optimize your algorithm?
- What if nums1's size is small compared to nums2's size? Which algorithm is better?
- What if elements of nums2 are stored on disk, and the memory is limited such that you cannot load all elements into the memory at once?
翻译:
给定两个数组,写一个函数来计算它们的交集。
示例:
给定nums1 = [1, 2, 2, 1]
,nums2 = [2, 2]
,返回[2, 2]
。
注意:
- 结果中的每个元素都应该显示在两个数组中显示的次数。
- 结果可以是任何顺序。
跟进:
- 如果给定的数组已经排序了怎么办?如何优化算法?
- 如果nums1的大小与nums2的大小相比会怎么样?哪种算法更好?
- 如果nums2的元素存储在磁盘上,并且内存受到限制,那么您不能一次将所有元素加载到内存中呢?
思路:
一开始思路是循环嵌套,无法实现重复元素的计算,看了答案,思路为把其中一个先装入map,值为个数,再遍历另一个数组,查找map,新建一个List存储相同的数字,最后list转数组并返回。
public int[] intersect(int[] nums1, int[] nums2) { Map<Integer,Integer> map = new HashMap<Integer,Integer>(); for(int i=0;i<nums1.length;i++){ if(map.containsKey(nums1[i])){ map.put(nums1[i],map.get(nums1[i])+1); }else{ map.put(nums1[i],1); } } List<Integer> list = new ArrayList<Integer>(); for(int i=0;i<nums2.length;i++){ if(map.containsKey(nums2[i]) && map.get(nums2[i])>0){ map.put(nums2[i],map.get(nums2[i])-1); list.add(nums2[i]); } } int[] r = new int[list.size()]; for(int i=0;i<list.size();i++){ r[i] = list.get(i); } return r; }
阅读全文
0 0
- oj350. Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays II
- Intersection of Two Arrays&Intersection of Two Arrays II
- [LeetCode] Intersection of Two Arrays II
- 350. Intersection of Two Arrays II
- 如何用SVG做出背景填充效果(avatar)
- java从入门到弃坑数据库0 0
- 直接插入排序
- React-JSX-常量定义与使用
- Java TCP 客户端和服务端之间的使用
- oj350. Intersection of Two Arrays II
- Python例题3-8 放眼世界
- Java注解
- 考研数学笔记 66~69
- POJ 1679 The Unique MST 笔记
- jquery无刷新添加和删除input输入框 增加减少input框
- C++类的构造函数
- matlab中基体函数的用法
- 填涂颜色(有意思的dfs)