Wildcards

Wildcardmatching/README.md

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+# Readme
+
+***Wild card matching using Dynamic Programming***
+
+This is a dynamic programing approach to match the given string with a given pattern.
+
+The pattern can be empty and can contain only lowercase letters a-z, and characters like ? or *.
+The string can be empty and can contain only lowercase letters a-z.
+
+'?' Matches any single character.
+'*' Matches any sequence of characters (including the empty sequence).
+
+The matching will cover the entire input string (not partial).
+
+***Example 1:***
+
+```Input:```
+s = "aa"
+p = "a"
+
+```Output:``` aa doesn't match with the given pattern: a?
+
+```Explanation:``` "a" does not match the entire string "aa".
+
+***Example 2:***
+
+```Input:```
+s = "aa"
+p = "*"
+
+```Output:``` aa matches the pattern: *?
+
+```Explanation:``` '*' matches any sequence.
+

Wildcardmatching/WildCard.java

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+
+import java.util.Scanner;
+public class WildCard 
+{
+	public static void main(String[] args) 
+	{
+		Scanner sc=new Scanner(System.in);
+		System.out.print("Enter a pattern: ");
+		String p=sc.nextLine();
+		while(true)
+		{
+			System.out.println("Enter a string (enter q to quit): ");
+			String string =sc.nextLine();
+			if(string.equals("q"))
+				break;
+			if(new WildCard().match(string, p))
+				System.out.println(string +" matches the pattern: "+ p+"\n");
+
+			else
+				System.out.println(string+ " doesn't match with the given pattern: "+p+"\n");
+		}
+		sc.close();
+	}
+
+    public boolean match(String S, String P) 
+    {
+        char[] string = S.toCharArray();
+        char[] pattern = P.toCharArray();
+        int m = string.length;
+        int n = pattern.length;
+        int pos = 0;
+        boolean isFirst = true;
+
+        for ( int i = 0 ; i < pattern.length; i++)	//Replacing multiple * with single * 
+        {
+            if (pattern[i] == '*') 
+            {
+                if (isFirst) 
+                {
+                    pattern[pos++] = pattern[i];
+                    isFirst = false;
+                }
+            } 
+            else 
+            {
+                pattern[pos++] = pattern[i];
+                isFirst = true;
+            }
+        }
+
+        boolean T[][] = new boolean[m + 1][n + 1];
+
+        if (pos > 0 && pattern[0] == '*') 
+            T[0][1] = true;
+
+        T[0][0] = true;
+
+        for (int i = 1; i < T.length; i++) 
+        {
+            for (int j = 1; j < T[0].length; j++) 
+            {
+                if (pattern[j-1] == '?' || string[i-1] == pattern[j-1]) 
+                {
+                    T[i][j] = T[i-1][j-1];
+                }
+                else if (pattern[j-1] == '*')
+                {
+                    T[i][j] = T[i-1][j] || T[i][j-1];
+                }
+            }
+        }
+
+        return T[m][pos];
+    }
+
+
+}

Wildcardmatching/input.txt

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+Enter a pattern: a*b?
+Enter a string (enter q to quit): 
+abcdefbh
+abcdefbh matches the pattern: a*b?
+
+Enter a string (enter q to quit): 
+abf
+abf matches the pattern: a*b?
+
+Enter a string (enter q to quit): 
+acdb
+acdb doesn't match with the given pattern: a*b?
+
+Enter a string (enter q to quit): 
+ab
+ab doesn't match with the given pattern: a*b?
+
+Enter a string (enter q to quit): 
+abfbfbfbf
+abfbfbfbf matches the pattern: a*b?
+
+Enter a string (enter q to quit): 
+q