Naive pattern search algorithm (#175)

* add naive pattern search algorithm

* add naive pattern search algorithm

Co-authored-by: Laptop-Salad <email.com>

src/strings/StringAlgo.jl

@@ -16,6 +16,7 @@ export word_count
 export hamming_distance
 export rabin_karp
 export LCS
+export naive_pattern_search
 
 include("detect_anagrams.jl")
 include("is_palindrome.jl")
@@ -25,5 +26,6 @@ include("word_count.jl")
 include("hamming_distance.jl")
 include("rabin_karp.jl")
 include("lcs.jl")
+include("naive_pattern_search.jl")
 
 end

src/strings/naive_pattern_search.jl

@@ -0,0 +1,44 @@
+"""
+naive_pattern_search(text, pattern)
+
+Program to find the given pattern in the given text
+
+# Arguments:
+- 'text': A string to find the pattern
+- 'pattern': A string to find in the given text
+
+# Examples/Tests
+```julia
+julia> naive_pattern_search("ABCDEF", "DEF")
+"DEF found at index: 3"
+
+julia> naive_pattern_search("Hello world!", "eggs")
+"No matches found"
+```
+
+# References:
+(https://www.geeksforgeeks.org/naive-algorithm-for-pattern-searching/)
+(https://www.tutorialspoint.com/Naive-Pattern-Searching)
+
+# Contributors:
+- [Laptop-Salad](https://github.com/Laptop-Salad)
+
+"""
+
+function naive_pattern_search(text, pattern)
+    for index in 0:(length(text)-length(pattern) + 1)
+        matches = 0
+        for character in eachindex(pattern)
+            if pattern[character] == text[index + character]
+                matches += 1
+
+                if matches == length(pattern)
+                    return string(pattern, " found at index: ", index)
+                end
+            else
+                break
+            end
+        end
+    end
+    return "No matches found"
+end

test/strings.jl

@@ -127,4 +127,14 @@ using TheAlgorithms.StringAlgo
 
         @test LCS("AGCDEG", "BGFDG") == "GDG"
     end
+
+    @testset "Strings: naive_pattern_search" begin
+        @test naive_pattern_search("ABCDEF", "DEF") == "DEF found at index: 3"
+
+        @test naive_pattern_search("Hello world!", "world") == "world found at index: 6"
+
+        @test naive_pattern_search("Hello world!", "world") == "world found at index: 6"
+
+        @test naive_pattern_search("ABCDEF", "XYZ") == "No matches found"
+    end
 end