#3407: Substring Matching Pattern; solution & tests

Author: vetalapo

c-sharp/Problems/arrays-and-hashing/SubstringMatchingPattern.cs

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+/**
+ * 3407
+ * Substring Matching Pattern
+ **
+ * You are given a string s and a pattern string p,
+ * where p contains exactly one '*' character.
+ * The '*' in p can be replaced with any sequence of zero or more characters.
+ *
+ * Return true if p can be made a substring of s, and false otherwise.
+ *
+ * Example 1:
+ *   Input: s = "leetcode", p = "ee*e"
+ *   Output: true
+ *   Explanation:
+ *     By replacing the '*' with "tcod",
+ *     the substring "eetcode" matches the pattern.
+ *
+ * Example 2:
+ *   Input: s = "car", p = "c*v"
+ *   Output: false
+ *   Explanation:
+ *     There is no substring matching the pattern.
+ *
+ * Example 3:
+ *   Input: s = "luck", p = "u*"
+ *   Output: true
+ *   Explanation:
+ *     The substrings "u", "uc", and "uck" match the pattern.
+ *
+ * Constraints:
+ *   • 1 <= s.length <= 50
+ *   • 1 <= p.length <= 50
+ *   • s contains only lowercase English letters.
+ *   • p contains only lowercase English letters and exactly one '*'
+ *
+ * Hint 1:
+ *   Divide the pattern in two strings and search in the string.
+ **
+ * https://leetcode.com/problems/substring-matching-pattern/
+***/
+
+using System;
+
+namespace Problems;
+
+public class SubstringMatchingPattern
+{
+    public bool HasMatch( ReadOnlySpan<char> s, ReadOnlySpan<char> p )
+    {
+        int i = p.IndexOf( '*' );
+
+        ReadOnlySpan<char> p1 = p[..i];
+
+        int first = s.IndexOf( p1 );
+
+        if ( first == -1 )
+        {
+            return false;
+        }
+
+        return s[( first + p1.Length )..]
+            .IndexOf( p[( i + 1 )..] ) != -1;
+    }
+}

c-sharp/Tests/arrays-and-hashing/SubstringMatchingPatternTests.cs

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+using NUnit.Framework;
+
+using Problems;
+
+public class SubstringMatchingPatternTests
+{
+    [TestCase( "leetcode", "ee*e", ExpectedResult = true )]
+    [TestCase( "car", "c*v", ExpectedResult = false )]
+    [TestCase( "luck", "u*", ExpectedResult = true )]
+    public bool HasMatchTest( string s, string p ) =>
+        new SubstringMatchingPattern().HasMatch( s, p );
+}