游程长度编码程序问题

Question

我是新来的Java和一般编程...我有一个问题实现运行长度编码程序，其中从用户输入的字符串。 （例如：KKKKKKKKKKKKKBCCDDDDDDDDDDDDDDDKKKKKMNUUUGGGGG)将基于标记字符进行编码它们的输入使特定字符串应该是这样的：？$K13BCC$D15$K5MNUUU$G5

有人能帮助我弄清楚什么是错的我不断收到这是我的输出：$K13BCC$D14$K4MNUUU

看来我的程序跳过最后一个字母，并在其中一些少了一个。任何帮助，将不胜感激！

我为乱码表示歉意。我知道这是不是很大，只是想弄清楚什么是错的这里...

import java.util.Scanner; 

public class RunLengthEncoding { 

    public static void main(String[] args) { 
     Scanner input = new Scanner(System.in); 

     System.out.print("Enter input string: "); 
     String inputString = input.next(); 

     System.out.print("Enter flag character: "); 
     String flagCharacter = input.next(); 

     Boolean validInput = false; 

     for (int i = 0; i < inputString.length(); i++) { 
      if (Character.isUpperCase(inputString.charAt(i))) { 
       validInput = true; 

      } else { 
       System.out.print("Bad input."); 
      } 

     } 

     char repeatedLetter = inputString.charAt(0); 

     if (validInput) { // if the input is valid, continue 
      int counter = 0; // set counter equal to 0 
      for (int i = 0; i < inputString.length(); i++) { // iterate through the input string 

       if (repeatedLetter == (inputString.charAt(i))) { // if the current letter is equal to the next 
        counter++; // increment the counter 
        repeatedLetter = inputString.charAt(i); // set the repeated letter to the next letter 
       } else { // if the current letter is not equal to the next letter 
        if (counter > 3) { // and if the counter is greater than 3 
         System.out.print(flagCharacter + repeatedLetter + counter); // print the encoded string 
        } else { // if the counter is not greater than 3 
         for (int j = counter; j >= 0; j--) { // for every number in counter 
          System.out.print(repeatedLetter); // print the current repeated letter for as many times as it appears 
         } 

        } 
        repeatedLetter = inputString.charAt(i); // set the new repeated letter 
        counter = 0; // reset counter to 0 

       } 
      } 

     } 

    } 

} 

Answer 1

首先，您应该在外部else块中将counter变量设置为1，因为您正在设置repeatedValue，并且该值计为该字母的单个计数。您还需要考虑到在你的字符串中的字符的最后一个序列，所以你需要你的循环之外的最后if语句，当你打到最后：

int counter = 0; // set counter equal to 0 
for (int i = 0; i < inputString.length(); i++) { // iterate through the input string 

    if (repeatedLetter == (inputString.charAt(i))) { // if the current letter is equal to the next 
     counter++; // increment the counter 
    } else { // if the current letter is not equal to the next letter 
     if (counter > 3) { // and if the counter is greater than 3 
      System.out.print(flagCharacter + repeatedLetter + counter); // print the encoded string 
     } else { // if the counter is not greater than 3 
      for (int j = counter; j > 0; j--) { // for every number in counter 
       System.out.print(repeatedLetter); // print the current repeated letter for as many times as it appears 
      } 

     } 
     repeatedLetter = inputString.charAt(i); // set the new repeated letter 
     counter = 1; // reset counter to 1 
    } 
} 

// We at the end of the string now, print everything else 
if (counter > 3) { // and if the counter is greater than 3 
    System.out.print(flagCharacter + repeatedLetter + counter); // print the encoded string 
} else { // if the counter is not greater than 3 
    for (int j = counter; j > 0; j--) { // for every number in counter 
     System.out.print(repeatedLetter); // print the current repeated letter for as many times as it appears 
    } 

} 

Answer 2

for循环状态是不太一样的用于初始字符计数和随后的字符计数。

与您的代码，我发现的最简单的解决是改变for循环

for (int i = 1; i < inputString.length(); i++) { // start at 1 not 0 

改变计数器初始化到1，而不是0在这两种情况下。

int counter = 1; // set counter equal to 1 

，不得不改变个性输出

for (int j = counter; j > 0; j--) { // for every number in counter 

也是最后一个字符运行没有被输出。

给

private static void process(String inputString, String flagCharacter) { 

    // init counter state 
    char repeatedLetter = inputString.charAt(0); 
    int counter = 1; 

    for (int i = 1; i < inputString.length(); i++) { 

     if (repeatedLetter == (inputString.charAt(i))) { 
      // match so update counter 
      counter++; 
     } else { 
      if (counter > 3) { 
       // counter needs to be above 3 to make worthwhile 
       System.out.print(flagCharacter + repeatedLetter + counter); 
      } else { 
       // otherwise we will just output raw 
       for (int j = counter; j > 0; j--) { 
        System.out.print(repeatedLetter); 
       } 

      } 
      // and re init our counter 
      repeatedLetter = inputString.charAt(i); 
      counter = 1; 
     } 

    } 

    // output last character run 
    if (counter > 3) { 
     System.out.print(flagCharacter + repeatedLetter + counter); 
    } else { 
     for (int j = counter; j > 0; j--) { 
      System.out.print(repeatedLetter); 
     } 
    } 

}