Problem 14: longest common prefix

problems/14-longest-common-prefix/main.rb

@@ -0,0 +1,26 @@
+# @param {String[]} strs
+# @return {String}
+def longest_common_prefix(strs)
+  # Find min length
+  min_length = strs[0].length
+  strs.each do |st|
+    if st.length < min_length
+      min_length = st.length
+    end
+  end
+  
+  res = ""
+  for i in 0..min_length - 1 do
+    strs.each do |st|
+      # If characters doesn't match
+      if st[i] != strs[0][i]
+        return res
+      end
+    end
+   
+    # All characters match
+    res += strs[0][i]
+  end
+
+  return res
+end

problems/14-longest-common-prefix/test.rb

@@ -0,0 +1,18 @@
+require_relative "main"
+require "test/unit"
+ 
+class TestLCP < Test::Unit::TestCase
+ 
+  def test_simple
+    assert_equal("fl", longest_common_prefix(["flower","flow","flight"]) )
+  end
+
+  def test_empty_prefix
+    assert_equal("", longest_common_prefix(["dog","racecar","car"]) )
+  end
+
+  def test_empty_string
+    assert_equal("", longest_common_prefix([""]) )
+  end
+
+end