博客
关于我
LeetCode 1122 数组的相对排序-简单-unordered_map容器的应用
阅读量:489 次
发布时间:2019-03-06

本文共 2250 字,大约阅读时间需要 7 分钟。

    
Relative Sort Arrays

Relative Sort Arrays Problem

Given two arrays, arr1 and arr2, where each element in arr2 is unique and appears in arr1, we need to sort arr1 such that the relative order of elements matches arr2. Elements not present in arr2 should be placed at the end in ascending order.

Example:

Input: arr1 = [2,3,1,3,2,4,6,7,9,2,19], arr2 = [2,1,4,3,9,6]

Output: [2,2,2,1,4,3,3,9,6,7,19]

Approach

To solve this problem, we can follow these steps:

  • Mapping Elements: First, create a mapping of each element in arr2 to its position. This helps in determining the required order of elements in arr1.
  • Sorting arr1: Sort the elements in arr1 based on their positions in arr2. Elements not present in arr2 are placed at the end in ascending order.

Implementation Steps

In code, we can implement this using a hash table (unordered_map) to store the positions of elements in arr2. Then, sort arr1 using a custom comparator that checks the positions from arr2. Finally, append any elements from arr1 that are not in arr2, sorted in ascending order.

Code Example

class Solution {public:    vector
relativeSortArray(vector
& arr1, vector
& arr2) { unordered_map
positionMap; // Populate the position map for (int i = 0; i < arr2.size(); ++i) { positionMap[arr2[i]] = i; } // Sort arr1 based on the position map sort(arr1.begin(), arr1.end(), [&positionMap](int a, int b) { return positionMap[a] < positionMap[b]; }); // Append elements from arr1 not present in arr2, sorted vector
extra; for (int num : arr1) { if (positionMap.find(num) == positionMap.end()) { extra.push_back(num); } } sort(extra.begin(), extra.end()); arr1.insert(arr1.end(), extra.begin(), extra.end()); return arr1; }

转载地址:http://ephdz.baihongyu.com/

你可能感兴趣的文章
MySQL事务隔离级别:读未提交、读已提交、可重复读和串行
查看>>
webpack css文件处理
查看>>
mysql二进制包安装和遇到的问题
查看>>
MySql二进制日志的应用及恢復
查看>>
mysql互换表中两列数据方法
查看>>
mysql五补充部分:SQL逻辑查询语句执行顺序
查看>>
mysql交互式连接&非交互式连接
查看>>
MySQL什么情况下会导致索引失效
查看>>
Mysql什么时候建索引
查看>>
MySql从入门到精通
查看>>
MYSQL从入门到精通(一)
查看>>
MYSQL从入门到精通(二)
查看>>
mysql以下日期函数正确的_mysql 日期函数
查看>>
mysql以服务方式运行
查看>>
mysql优化--索引原理
查看>>
MySQL优化之BTree索引使用规则
查看>>
MySQL优化之推荐使用规范
查看>>
Webpack Critical CSS 提取与内联教程
查看>>
mysql优化概述(范式.索引.定位慢查询)
查看>>
MySQL优化的一些需要注意的地方
查看>>