在C＃中比較一個2D和一個一維數組？

Question

我只是想編寫比較一維數組與二維數組的代碼......我正在編寫一個編譯器，並且想要比較一個包含我的代碼的一維數組和其中我已經創建了一個符號表的一維數組。 我寫了代碼，但它不工作。

for (int x = 0; x < symboltable1.Length; x++) 
{ 
    for (int y = 0; y < symboltable1.Length; y++) 
    { 
     for (int z = 0; z < text.Length; z++) 
     { 
      if (symboltable1[x,y] == text[z]) 
       listBox2.Items.Add(text[z]); 
      else 
       MessageBox.Show("poor"); 
     } 
    } 
} 

Answer 1

你的方法太慢O（N * M * L）（其中升是文本的長度，ñ & 米你的符號表的尺寸。）

將您的符號表轉換爲排序後的索引表會給你一個O（l * log（n * m）），並且使用散列表會給你一個幾乎O（l）。

我實現了三個辦法只是爲了好玩：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 

namespace test 
{ 
    class Program 
    { 
     class IndexElement:IComparable<IndexElement> 
     { 
      public string value; 
      public int x; 
      public int y; 
      public IndexElement(string v,int x,int y) 
      { 
       this.value = v; 
       this.x = x; 
       this.y = y; 
      } 

      public int CompareTo(IndexElement other) 
      { 
       return value.CompareTo(other.value); 
      } 
     } 

     struct Position 
     { 
      public int x; 
      public int y; 
      public Position(int x, int y) 
      { 
       this.x = x; 
       this.y = y; 
      } 
     } 
     static void Main(string[] args) 
     { 
      string[,] symbols = new string[,] { { "if", "else" }, { "for", "foreach" }, { "while", "do" } }; 
      string[] text = new string[] { "for", "int", "in", "if", "then" }; 
      Dictionary<string, Position> dictionary = BuildDict(symbols); 
      IndexElement[] index = BuildIndex(symbols); 
      Console.WriteLine("Brute:"); 
      foreach (string s in CompareUsingBrute(text, symbols)) 
      { 
       Console.WriteLine(s); 
      } 
      Console.WriteLine("Dict:"); 
      foreach (string s in CompareUsingIndex(text, dictionary)) 
      { 
       Console.WriteLine(s); 
      } 
      Console.WriteLine("Indexing:"); 
      foreach (string s in CompareUsingDictionary(text, index)) 
      { 
       Console.WriteLine(s); 
      } 
      Console.ReadKey(); 
     } 

     private static List<string> CompareUsingBrute(string[] text, string[,] symbols) 
     { 
      List<string> res = new List<string>(); 
      for (int x = 0; x < symbols.GetLength(0); x++) 
      { 
       for (int y = 0; y < symbols.GetLength(1); y++) 
       { 
        for (int z = 0; z < text.Length; z++) 
        { 
         if (symbols[x, y] == text[z]) 
          res.Add(text[z]);       
        } 
       } 
      } 
      return res; 

     } 

     private static List<string> CompareUsingDictionary(string[] text, IndexElement[] index) 
     { 
      List<string> res = new List<string>(); 
      foreach (string s in text) 
      { 
       if (Array.BinarySearch<IndexElement>(index, new IndexElement(s, 0, 0)) >= 0) 
       { 
        res.Add(s); 
       } 
      } 
      return res; 
     } 

     private static IndexElement[] BuildIndex(string[,] symbols) 
     { 
      IndexElement[] res = new IndexElement[symbols.Length]; 
      int index = 0; 
      for (int i = 0; i < symbols.GetLength(0); i++) 
      { 
       for (int j = 0; j < symbols.GetLength(1); j++) 
       { 
        res[index] = new IndexElement(symbols[i, j], i, j); 
        index++; 
       } 

      } 
      Array.Sort(res); 
      return res; 
     } 

     private static List<string> CompareUsingIndex(string[] text, Dictionary<string, Position> dictionary) 
     { 
      List<string> res = new List<string>(); 
      foreach (string s in text) 
      { 
       Position p; 
       if (dictionary.TryGetValue(s,out p)) 
       { 
        res.Add(s); 
       } 
      } 
      return res; 
     } 

     private static Dictionary<string, Position> BuildDict(string[,] symbols) 
     { 
      Dictionary<string, Position> res = new Dictionary<string, Position>(); 
      for (int i = 0; i < symbols.GetLength(0); i++) 
      { 
       for (int j = 0; j < symbols.GetLength(1); j++) 
       { 
        res.Add(symbols[i, j], new Position(i, j)); 
       } 
      } 
      return res; 
     } 


    } 
} 

Answer 2

我想你的錯誤可能是在檢查數組長度。
試試這個：

for (int x = 0; x < symboltable1.GetLength(0); x++) 
{ 
    for (int y = 0; y < symboltable1.GetLength(1); y++) 
    { 
     for (int z = 0; z < text.Length; z++) 
     { 
      if (symboltable1[x,y] == text[z]) 
       listBox2.Items.Add(text[z]); 
      else 
       MessageBox.Show("poor"); 
     } 
    } 
}