fix some file extensions

Task/Longest-common-subsequence/CoffeeScript/longest-common-subsequence.coffee

@@ -0,0 +1,30 @@
+lcs = (s1, s2) ->
+  len1 = s1.length
+  len2 = s2.length
+
+  # Create a virtual matrix that is (len1 + 1) by (len2 + 1),
+  # where m[i][j] is the longest common string using only
+  # the first i chars of s1 and first j chars of s2.  The
+  # matrix is virtual, because we only keep the last two rows
+  # in memory.
+  prior_row = ('' for i in [0..len2])
+
+  for i in [0...len1]
+    row = ['']
+    for j in [0...len2]
+      if s1[i] == s2[j]
+        row.push prior_row[j] + s1[i]
+      else
+        subs1 = row[j]
+        subs2 = prior_row[j+1]
+        if subs1.length > subs2.length
+          row.push subs1
+        else
+          row.push subs2
+    prior_row = row
+
+  row[len2]
+
+s1 = "thisisatest"
+s2 = "testing123testing"
+console.log lcs(s1, s2)