2017算法课.10(Find All Numbers Disappeared in an Array)
来源:互联网 发布:javascript charat 编辑:程序博客网 时间:2024/05/24 02:51
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]
题目大意:
给定一个整数数组,其中1 ≤ a[i] ≤ n (n = 数组长度),一些元素出现两次,其他的出现一次。
寻找所有[1, n]中没有出现在数组中的元素。
可以不使用额外空间并在O(n)运行时间求解吗?你可以假设返回列表不算额外空间。
解题思路:
正负号标记法
遍历数组nums,记当前元素为n,令nums[abs(n) - 1] = -abs(nums[abs(n) - 1])
再次遍历nums,将正数对应的下标+1返回即为答案,因为正数对应的元素没有被上一步骤标记过。
class Solution {
public:
vector<int> findDisappearedNumbers(vector<int>& nums) {
int len = nums.size();
for(int i=0; i<len; i++) {
int m = abs(nums[i])-1;
nums[m] = nums[m]>0 ? -nums[m] : nums[m];
}
vector<int> res;
for(int i = 0; i<len; i++) {
if(nums[i] > 0) res.push_back(i+1);
}
return res;
}
};
- 2017算法课.10(Find All Numbers Disappeared in an Array)
- Find All Numbers Disappeared in an Array
- Find All Numbers Disappeared in an Array
- Find All Numbers Disappeared in an Array
- Find All Numbers Disappeared in an Array
- Find All Numbers Disappeared in an Array
- Find All Numbers Disappeared in an Array
- Find All Numbers Disappeared in an Array
- Find All Numbers Disappeared in an Array
- Find All Numbers Disappeared in an Array
- Find All Numbers Disappeared in an Array
- Find All Numbers Disappeared in an Array
- Find All Numbers Disappeared in an Array
- 448. Find All Numbers Disappeared in an Array(C++)
- Find All Numbers Disappeared in an Array(哈希表)
- leetcode 448Find All Numbers Disappeared in an Array (array)
- LeetCode-Array-448. Find All Numbers Disappeared in an Array
- LeetCode OJ|Array|Find All Numbers Disappeared in an Array
- Spring设计及源码分析
- 面试题61:按之字形顺序打印二叉树
- 基于Lucene的搜索引擎的建立
- 用Java2D画出树的结构图
- DPMM(狄利克雷过程混合模型)浅解和添加似然函数的问题
- 2017算法课.10(Find All Numbers Disappeared in an Array)
- 设计学校官网框架
- 关于联表的处理
- 史上最简单的 MySQL 教程(四)「SQL 基本操作 之 库操作」
- 144.看门狗的bug
- QT学习(二)部分总结
- 人工智能
- 东软集团业务的波特五力模型分析
- POJ 3253 Fence Repair(贪心+优先队列)