zoukankan      html  css  js  c++  java
  • 【leetcode】1338. Reduce Array Size to The Half

    题目如下:

    Given an array arr.  You can choose a set of integers and remove all the occurrences of these integers in the array.

    Return the minimum size of the set so that at least half of the integers of the array are removed.

    Example 1:

    Input: arr = [3,3,3,3,5,5,5,2,2,7]
    Output: 2
    Explanation: Choosing {3,7} will make the new array [5,5,5,2,2] which has size 5 (i.e equal to half of the size of the old array).
    Possible sets of size 2 are {3,5},{3,2},{5,2}.
    Choosing set {2,7} is not possible as it will make the new array [3,3,3,3,5,5,5] which has size greater than half of the size of the old array.
    

    Example 2:

    Input: arr = [7,7,7,7,7,7]
    Output: 1
    Explanation: The only possible set you can choose is {7}. This will make the new array empty.
    

    Example 3:

    Input: arr = [1,9]
    Output: 1
    

    Example 4:

    Input: arr = [1000,1000,3,7]
    Output: 1
    

    Example 5:

    Input: arr = [1,2,3,4,5,6,7,8,9,10]
    Output: 5

    Constraints:

    • 1 <= arr.length <= 10^5
    • arr.length is even.
    • 1 <= arr[i] <= 10^5

    解题思路:贪心算法,从出现次数最多的元素的删起,然后删除次多的元素,直到满足条件为止。

    代码如下:

    class Solution(object):
        def minSetSize(self, arr):
            """
            :type arr: List[int]
            :rtype: int
            """
            dic = {}
            val = []
            for i in arr:
                dic[i] = dic.setdefault(i,0) + 1
            
            
            for i in dic:
                val.append(dic[i])
            val.sort()
            
            count = 0
            total = 0
            for i in val[::-1]:
                total += i
                count += 1
                if total >= len(arr)/2:
                    break
            return count 
            
  • 相关阅读:
    Linux命令笔记
    Linux服务安装集合(1)
    浅谈GIT之通讯协议
    浅谈GIT之底层对象理解
    友情链接
    当黑客被抓是种怎样的体验?
    PHP 中 include 和 require 的区别详解
    论假如有一台无限算力的主机
    msf渗透安卓手机
    aws ec2 安装Elastic search 7.2.0 kibana 并配置 hanlp 分词插件
  • 原文地址:https://www.cnblogs.com/seyjs/p/12283376.html
Copyright © 2011-2022 走看看