leetcode 448. Find All Numbers Disappeared in an Array

Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once.

Find all the elements of [1, n] inclusive that do not appear in this array.

Could you do it without extra space and in O(n) runtime? You may assume the returned list does not count as extra space.

Example:

Input:
[4,3,2,7,8,2,3,1]Output:
[5,6]
解法：因为要修改输入，个人觉得这并不是一个优雅的解法。

class Solution(object):def findDisappearedNumbers(self, nums):""":type nums: List[int]:rtype: List[int]"""# use nums as a map# if x in nums appear, set nums[x] to negative# if [1,n] in map, map it with negative numberfor n in nums:i = abs(n)-1if nums[i]>0:nums[i] = -nums[i]return [i for i in xrange(1, len(nums)+1) if nums[i-1]>0]

解法2:排序，将数值放到对应位置上。使用贪心算法！

class Solution(object):def findDisappearedNumbers(self, nums):""":type nums: List[int]:rtype: List[int]"""# sort num in nums to its right position# for each num, use greedy algo to move num to its right pos, until nums[i] = i+1 # for example:# [4,3,2,7,8,2,3,1]# [7,3,2,4,8,2,3,1]# [3,3,2,4,8,2,7,1]# [2,3,3,4,8,2,7,1]# [3,2,3,4,8,2,7,1]# pos 3 is 3 end# [3,2,3,4,8,2,7,1]# [3,2,3,4,1,2,7,8]# [1,2,3,4,3,2,7,8]# pos 3 is 3 end# ...for i,n in enumerate(nums):while nums[nums[i]-1] != nums[i]:nums[nums[i]-1], nums[i] = nums[i], nums[nums[i]-1]return [i+1 for i,n in enumerate(nums) if n!=i+1]

转载于:https://www.cnblogs.com/bonelee/p/8589088.html

leetcode 448. Find All Numbers Disappeared in an Array相关推荐

Leetcode 448. Find All Numbers Disappeared in an Array
Leetcode 448. Find All Numbers Disappeared in an Array Add to List Description Submission Solutions ...
LeetCode 448. Find All Numbers Disappeared in an Array 442. Find All Duplicates in an Array
这两道题很有意思,由于元素为1~n,因此每个元素的值-1(映射到0~n-1)就可以直接当做下标.这样将 nums 中对应下标的元素 *-1 以i表示 index+1 这个元素出现过了,能节省存储的空间 ...
leetcode 448. Find All Numbers Disappeared in an Array | 448. 找到所有数组中消失的数字（原地，位运算）
题目 https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array/ 题解遍历数组,将数组中每个数字 n 作为下标,将 ...
[swift] LeetCode 448. Find All Numbers Disappeared in an Array
Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and ot ...
LeetCode之Find All Numbers Disappeared in an Array
1.题目 Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice a ...
448. Find All Numbers Disappeared in an Array(找到所有数组中消失的数字)
Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and ot ...
448. Find All Numbers Disappeared in an Array
Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and ot ...
448. Find All Numbers Disappeared in an Array 寻找有界数组[1,n]中的缺失数
［抄题］: Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice ...
448. Find All Numbers Disappeared in an Array645. Set Mismatch
题目: 448. Find All Numbers Disappeared in an Array Given an array of integers where 1 ≤ a[i] ≤ n (n = ...

leetcode 448. Find All Numbers Disappeared in an Array

leetcode 448. Find All Numbers Disappeared in an Array相关推荐

最新文章

热门文章