From 548c2fd9d04bc65fc2ae555ab83a1868d7dabd7e Mon Sep 17 00:00:00 2001
From: "duaraghav8@gmail" <duaraghav8@gmail.com>
Date: Tue, 24 May 2016 00:33:40 +0530
Subject: [PATCH] Add category String & Edit Distance Algorithm

---
 algorithm/category.json                       |  6 +++
 algorithm/string/edit_distance/desc.json      | 18 +++++++++
 .../edit_distance/dynamic_programming/code.js | 40 +++++++++++++++++++
 .../edit_distance/dynamic_programming/data.js | 10 +++++
 4 files changed, 74 insertions(+)
 create mode 100644 algorithm/string/edit_distance/desc.json
 create mode 100644 algorithm/string/edit_distance/dynamic_programming/code.js
 create mode 100644 algorithm/string/edit_distance/dynamic_programming/data.js

diff --git a/algorithm/category.json b/algorithm/category.json
index 528e8276..415d28b1 100644
--- a/algorithm/category.json
+++ b/algorithm/category.json
@@ -27,6 +27,12 @@
       "heap" : "Heap Sort"
     }
   },
+  "string": {
+   		"name": "String",
+   		"list": {
+   			"edit_distance": "Edit Distance"
+   		}
+   },
   "etc": {
     "name": "Uncategorized",
     "list": {
diff --git a/algorithm/string/edit_distance/desc.json b/algorithm/string/edit_distance/desc.json
new file mode 100644
index 00000000..d945d7bb
--- /dev/null
+++ b/algorithm/string/edit_distance/desc.json
@@ -0,0 +1,18 @@
+{
+  "Edit-Distance": "Given two strings str1 (length M) and str2 (length N) and below operations that can performed on str1. Find minimum number of edits (operations) required to convert str1 into str2.<br />Insert<br />Remove<br />Replace<br />All of the above operations are of equal cost",
+  "Applications": [
+    "Displaing Near-Proximity Words",
+    "Information Retrieval (eg- Lucene API)",
+    "Natural Language Processing"
+  ],
+  "Complexity": {
+    "time": "worst O(|M|.|N|)",
+    "space": "worst O(|M|.|N|)"
+  },
+  "References": [
+    "<a href='https://en.wikipedia.org/wiki/Edit_distance'>Wikipedia</a>"
+  ],
+  "files": {
+    "dynamic_programming": "Distance from str1 to str2 using Dynamic Programming (2D Array method)"
+  }
+}
diff --git a/algorithm/string/edit_distance/dynamic_programming/code.js b/algorithm/string/edit_distance/dynamic_programming/code.js
new file mode 100644
index 00000000..4373ab71
--- /dev/null
+++ b/algorithm/string/edit_distance/dynamic_programming/code.js
@@ -0,0 +1,40 @@
+tracer._pace (200);
+tracer._print ('Initialized DP Table');
+tracer._print ('Y-Axis (Top to Bottom): ' + str1);
+tracer._print ('X-Axis (Left to Right): ' + str2);
+
+var dist = (function editDistance (str1, str2, table) {
+	//display grid with words
+	tracer._print ('*** ' + str2.split ('').join (' '));
+	table.forEach (function (item, index) {
+		var character = (index === 0) ? '*' : str1 [index-1];
+		tracer._print (character + '\t' + item);
+	});
+
+	//begin ED execution
+	for (var i = 1; i < str1.length+1; i++) {
+		for (var j = 1; j < str2.length+1; j++) {
+			if (str1 [i-1] === str2 [j-1]) {
+				tracer._select (i-1, j-1);
+				table [i] [j] = table [i-1] [j-1];
+				tracer._notify (i, j);
+				tracer._deselect (i-1, j-1);
+			}
+			else {
+				tracer._select (i-1, j);
+				tracer._select (i, j-1);
+				tracer._select (i-1, j-1);
+				table [i] [j] = Math.min (table [i-1] [j], table [i] [j-1], table [i-1] [j-1]) + 1;
+				tracer._notify (i, j);
+				tracer._deselect (i-1, j);
+				tracer._deselect (i, j-1);
+				tracer._deselect (i-1, j-1);
+			}
+		}
+	}
+
+	tracer._select (str1.length, str2.length);
+	return table [str1.length] [str2.length];
+}) (str1, str2, table);
+
+tracer._print ('Minimum Edit Distance: ' + dist);
\ No newline at end of file
diff --git a/algorithm/string/edit_distance/dynamic_programming/data.js b/algorithm/string/edit_distance/dynamic_programming/data.js
new file mode 100644
index 00000000..86eae52d
--- /dev/null
+++ b/algorithm/string/edit_distance/dynamic_programming/data.js
@@ -0,0 +1,10 @@
+var tracer = new Array2DTracer ();
+var str1 = 'stack', str2 = 'racket', table = new Array (str1.length + 1);
+
+table [0] = Array.apply (null, {length: str2.length + 1}).map (Number.call, Number);
+for (var i = 1; i < str1.length+1; i++) {
+	table [i] = Array.apply (null, Array (str2.length+1)).map (Number.prototype.valueOf, -1);
+	table [i] [0] = i
+}
+
+tracer._setData (table);
\ No newline at end of file