From 5b3efe8d2c59c8805184e66e461d1d6fd8eede0a Mon Sep 17 00:00:00 2001
From: Thivagar Manickam <thivagar200@gmail.com>
Date: Sat, 1 Aug 2020 09:42:36 +0530
Subject: [PATCH] Added string pattern matching algorithm

---
 String/PatternMatching.js | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 String/PatternMatching.js

diff --git a/String/PatternMatching.js b/String/PatternMatching.js
new file mode 100644
index 0000000000..b6b64bb5b3
--- /dev/null
+++ b/String/PatternMatching.js
@@ -0,0 +1,36 @@
+/*
+Pattern matching is case insensitive as
+the inputs are converted to lower case before the
+algorithm is run.
+
+The algorithm will run through the entire text and
+return the starting index if the given pattern is
+available in the text
+*/
+const checkIfPatternExists = (text, pattern) => {
+  const textLength = text.length // Store the length of the text in a variable
+  const patternLength = pattern.length // Store the length of the pattern in a variable
+
+  // Iterate through the text until the textlength - patternlength index
+  for (let i = 0; i <= textLength - patternLength; i++) {
+    // For each character in the text check if the subsequent character
+    // are matching the given pattern; if not break from the condition
+    for (let j = 0; j < textLength; j++) {
+      if (text[i + j] !== pattern[j]) break
+
+      // For each iteration of j check if the value of
+      // j + 1 is equal to the length of the pattern
+      if (j + 1 === patternLength) {
+        console.log(`Given pattern is found at index ${i}`)
+      }
+    }
+  }
+}
+
+const main = () => {
+  const text = 'AABAACAADAABAAAABAA'
+  const pattern = 'AABA'
+  checkIfPatternExists(text.toLowerCase(), pattern.toLowerCase())
+}
+
+main()