zoukankan      html  css  js  c++  java
  • 1647. Minimum Deletions to Make Character Frequencies Unique

    package LeetCode_1647
    
    import java.util.*
    import kotlin.collections.HashMap
    
    /**
     * 1647. Minimum Deletions to Make Character Frequencies Unique
     * https://leetcode.com/problems/minimum-deletions-to-make-character-frequencies-unique/
     *
     * A string s is called good if there are no two different characters in s that have the same frequency.
    Given a string s, return the minimum number of characters you need to delete to make s good.
    The frequency of a character in a string is the number of times it appears in the string.
    For example, in the string "aab", the frequency of 'a' is 2, while the frequency of 'b' is 1.
    
    Example 1:
    Input: s = "aab"
    Output: 0
    Explanation: s is already good.
    
    Example 2:
    Input: s = "aaabbbcc"
    Output: 2
    Explanation: You can delete two 'b's resulting in the good string "aaabcc".
    Another way it to delete one 'b' and one 'c' resulting in the good string "aaabbc".
    
    Example 3:
    Input: s = "ceabaacb"
    Output: 2
    Explanation: You can delete both 'c's resulting in the good string "eabaab".
    Note that we only care about characters that are still in the string at the end (i.e. frequency of 0 is ignored).
    
    Constraints:
    1. 1 <= s.length <= 105
    2. s contains only lowercase English letters.
     * */
    class Solution {
        /*
        * solution: HashMap + HashSet, map to calculate appearance count, set to help reduce duplicate appearacne count
        * Time complexity:O(n), Space complexity:O(n)
        * */
        fun minDeletions(s: String): Int {
            val map = HashMap<Char, Int>()
            for (c in s) {
                map.put(c, map.getOrDefault(c, 0) + 1)
            }
            var result = 0
            val set = HashSet<Int>()
            for (item in map) {
                var value = item.value
                while (set.contains(value)) {//contains in HashSet is O(1)
                    value--
                    result++
                }
                if (value > 0) {
                    set.add(value)
                }
            }
            return result
        }
    }
  • 相关阅读:
    mysql子查询
    hibernate lazy属性true false extra 抓取策略
    unittest下,生成的测试报告
    python创建excel文件,并进行读与存操作
    configparser模块简介
    PyCharm里面的c、m、F、f、v、p分别代表什么含义?
    Python之路(第十七篇)logging模块
    configparser模块简介
    python中os.sep的作用以及sys._getframe().f_back.f_code.co_xxx的含义
    os.getcwd()和os.path.realpath(__file__)的区别
  • 原文地址:https://www.cnblogs.com/johnnyzhao/p/13943965.html
Copyright © 2011-2022 走看看