[leetcode] 238. Product of Array Except Self 解题报告
来源:互联网 发布:路由器网络不稳定 编辑:程序博客网 时间:2024/05/16 07:27
题目链接:https://leetcode.com/problems/product-of-array-except-self/
Given an array of n integers where n > 1, nums
, return an array output
such that output[i]
is equal to the product of all the elements of nums
except nums[i]
.
Solve it without division and in O(n).
For example, given [1,2,3,4]
, return [24,12,8,6]
.
Follow up:
Could you solve it with constant space complexity? (Note: The output array does not count as extra space for the purpose of space complexity analysis.)
思路:如果没有限制,最简单的思路当然是得到所有的乘积然后除以当前这一位数。既然不让用除,那么也可以用两个数组来保存[0, i]区间的乘积和[i, n-1]的乘积,然后在求结果的时候乘以左右边的乘积即可,这种空间复杂度是O(n)。
但是后来又限制空间复杂度,我们可以从左到右扫描一遍得到前面部分的乘积,再从右到左扫描一遍得到后半部分的乘积,然后将其相乘即是最终结果。
盗用水中的鱼blog的一张图,下图表明操作的流程
代码如下:
class Solution {public: vector<int> productExceptSelf(vector<int>& nums) { int len = nums.size(); vector<int> result(len); result[0] = 1; for(int i = 1; i < len; i++) result[i] = result[i-1]*nums[i-1]; int tem =1; for(int i = len -2; i>= 0; i--) { tem *= nums[i+1]; result[i] = result[i] * tem; } return result; }};参考:http://fisherlei.blogspot.com/2015/10/leetcode-product-of-array-except-self.html
0 0
- [leetcode] 238. Product of Array Except Self 解题报告
- LeetCode OJ 238. Product of Array Except Self 解题报告
- LeetCode 238. Product of Array Except Self 解题报告
- leetcode解题报告:238. Product of Array Except Self
- 【LeetCode】238. Product of Array Except Self解题报告
- [Leetcode] 238. Product of Array Except Self 解题报告
- [LeetCode]Product of Array Except Self,解题报告
- [leetcode] 238.Product of Array Except Self
- [LeetCode]238.Product of Array Except Self
- [leetcode] 238. Product of Array Except Self
- Leetcode 238. Product of Array Except Self
- [LeetCode]238. Product of Array Except Self
- 238. Product of Array Except Self LeetCode
- LeetCode 238. Product of Array Except Self
- [LeetCode]238. Product of Array Except Self
- LeetCode *** 238. Product of Array Except Self
- LeetCode 238. Product of Array Except Self
- 【leetcode】238. Product of Array Except Self
- 40个Java多线程问题总结
- [转载]辨析access_ok put_user __put_user get_user __get_user
- Type mismatch: cannot convert from Integer to int(java 报错)
- 普通程序员通向架构师的最佳路径?
- Android:如何为APP添加满屏启动页
- [leetcode] 238. Product of Array Except Self 解题报告
- 关于资源的Reference路径引用下,文件的使用
- mybatis之mysql&oracle 批量操作
- InfoPath表单每增加一个表单产生一个自动增加ID序号
- 程序员必须知道的几个Git代码托管平台
- Xcode编译Undefined symbols for architecture xxx 错误总结
- 29. 在magento CMS中的标签变量使用
- 纯css3实现点击缩略图切换背景图
- windows+caffe+vs2013+cuda6.5配置记录