Question

我正在尝试编写一个程序，它将从文本文件中的单词写出最长和最短的回文。我的代码现在看起来像这样：

    static void Main(string[] args)
    {
        string[] lines = System.IO.File.ReadAllLines(@"C:\palindromy.txt");

        foreach (string line in lines)
        {
            char[] charArray = line.ToCharArray();
            for (int i = 0; i < 1; i++)
            {
                Array.Reverse(charArray);
                bool a = charArray.SequenceEqual(line);
                while(a == true)
                {                        
                    Console.WriteLine(line); /that will just write all palindroms
                    break;
                }
            }
        }
    }

我目前正在写所有的回文，但我需要写出最长和最短的回文。

Answer 1

 static void Main(string[] args)
    {
        string[] lines = System.IO.File.ReadAllLines(@"C:\palindromy.txt");
        private string longest;
        private string shortest;
        foreach (string line in lines)
        {
            char[] charArray = line.ToCharArray();
            for (int i = 0; i < 1; i++)
            {
                Array.Reverse(charArray);
                bool a = charArray.SequenceEqual(line);
                if(a)
                {
                      if(a.Length > longest.length)
                         {
                              longest = a;
                         }
                      if(a.Length<shortest.length)
                         {
                            shortest = a;
                         }
                }
            }
        }

           Console.WriteLine(longest);
           Console.WriteLine(shortest);
    }

从头顶看，它看起来像这样。

Answer 2

与之前的答案类似，但提出以下建议

初始化最长和最短。
比较时忽略大小写。仍然可以使用SequenceEqual而不是比较字符串。如果您知道您不会将Anna与annA进行比较，则可能不需要。

检查您是否找到最短时间时，需要记住这一点 shortest.Length与0开始，所以你会想要存储最短的第一个回文，如果最短的话.Length == 0.

static void Main(string[] args)
{
    var lines = System.IO.File.ReadAllLines(@"C:\palindromy.txt");

    string longest = string.Empty;
    string shortest = string.Empty;

    foreach (var line in lines)
    {
        if (line.Length == 0) continue;

        char[] charArray = line.ToCharArray();
        Array.Reverse(charArray);
        string reversedLine = new string(charArray);

        if (line.Equals(reversedLine, StringComparison.OrdinalIgnoreCase))
        {
            if (line.Length > longest.Length)
            {
                longest = line;
            }
            if (line.Length < shortest.Length || shortest.Length == 0)
            {
                shortest = line;
            }
        }
    }

    Console.WriteLine(longest);
    Console.WriteLine(shortest);
}

Answer 3

如果你使用一些LINQ，你可以在很大程度上简化它：

string[] lines = System.IO.File.ReadAllLines(@"C:\palindromy.txt");
var palindromes = lines.Where(x => x == new string(x.ToCharArray()
                       .Reverse()
                       .ToArray()));

var shortest = palindromes.Aggregate((a, b) => a.Length < b.Length ? a : b);
var longest = palindromes.Aggregate((a, b) => a.Length > b.Length ? a : b);

Console.WriteLine("The shortest palindrome is {0}.", shortest);
Console.WriteLine("The longest palindrome is {0}.", longest);

Answer 4

这是一个简单的控制台应用程序，可以完全满足您的要求。单词位于List，因此您必须阅读文本文件中的单词并将其存储在List中。

using System;
using System.Collections;
using System.Collections.Generic;

namespace PalinDromes
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            List<string> words = new List<string> () { "anotherword","civic", "deified", "lemel", "pop" ,"noon"};

            string shortest = "";
            string longest = "";

            foreach (string word in words) 
            {
                if (isPalindrome (word)) 
                {
                    if (word.Length > longest.Length)
                        longest = word;
                    else if (shortest == "" || word.Length < shortest.Length)
                        shortest = word;
                }
            }

            Console.WriteLine ("Shortest: {0}", shortest);
            Console.WriteLine ("Longest: {0}", longest);
        }

        public static bool isPalindrome(string word)
        {
            return word == ReverseString (word);
        }

        public static string ReverseString(string s)
        {
            char[] arr = s.ToCharArray();
            Array.Reverse(arr);
            return new string(arr);
        }
    }
}

从文本文件中写出最长和最短的回文

4 个答案: