python 游程编码

Problem description

问题描述

Write a program that counts frequency of each letter in the string (string consists lowercase letters only).

编写一个程序来计算字符串中每个字母的频率 (字符串仅包含小写字母)。

Solution:

解：

Algorithm

算法

1. Initialize an array of 26 elements for each letter (a-z) to 0. (array[26]={0})

   将每个字母(az)初始化为26个元素的数组，以将其设置为0。( array [26] = {0} )

2. Scan the entire string and for each string element check the letter and increase the frequency in array by using ASCII value. (array[str[i]-'a']++)

   扫描整个字符串，并为每个字符串元素检查字母，并使用ASCII值增加数组中的频率。 ( array [str [i]-'a'] ++ )

   Like in

   像

   str="aaabbccccddef",

   str =“ aaabbccccddef” ，

   str [3] ='b'

   str [3] ='b'

   Thus, and

   因此，

   str [2]-'a'=1

   str [2]-'a'= 1

   Thus it increases the frequency of

   因此，它增加了频率

   'b' by 1 (array [str [3]-'a'] turns to be array [1] ++)

   “ b”乘以1(数组[str [3]-'a']变成数组[1] ++ )

3. Finally print the letter with their respective frequencies. This is the encoded string.

   最后，以相应的频率打印字母。 这是编码的字符串。

C ++程序查找/打印字符串中字母的频率 (C++ program to find/print frequency of letters in a string)

#include <bits/stdc++.h>
using namespace std;
void freq(string s){//array to store frequency of 26 characters,initialized to 0
int arr[26]={0};
for(int i=0;i<s.length();i++){// s[i] is the ascii value of the letter at index i & 'a'
//also gives the ascii value of a, in this way we are
//checking which alphabet is at index i and increasing its frequency
arr[s[i]-'a']++;
}
for(int i=0;i<26;i++){
if(arr[i]!=0)
printf("%d%c",arr[i],'a'+i);
}
cout<<endl;
}
int main(){string s;
cout<<"enter string\n";
cin>>s;
cout<<"encoded string is : "<<endl;
freq(s);
return 0;
}

Output

输出量

enter string
aaaabbcccccddf
encoded string is :
4a2b5c2d1f

翻译自: https://www.includehelp.com/icp/run-length-encoding-print-frequency-of-letters-in-a-string.aspx

python 游程编码