diff --git a/leet_942.rb b/leet_942.rb
new file mode 100644
index 0000000..b560d33
--- /dev/null
+++ b/leet_942.rb
@@ -0,0 +1,19 @@
+# https://leetcode.com/problems/DI String Match/
+# Runtime: 160 ms, faster than 70.83% of Python3 online submissions for DI String Match
+def di_string_match(s)
+  l = s.length-1
+  lo=0
+  hi=l+1
+  ans=[]
+  (0..l).each do |i|
+    if s[i].eql?('I')
+      ans[i]=lo
+      lo+=1
+    else
+      ans[i]=hi
+      hi-=1
+    end
+  end
+  ans[l+1]=lo
+  return ans
+end