--- a/julia/dp.jl	Thu Mar 02 20:51:07 2023 +0100
+++ b/julia/dp.jl	Thu Mar 02 23:06:32 2023 +0100
@@ -379,3 +379,26 @@
         end
     end
 end
+
+function shortest_common_supersequence(x::AbstractString, y::AbstractString, i=1, j=1)::Int
+    if i > length(x)
+        return length(y)-j+1
+    end
+    if j > length(y)
+        return length(x)-i+1
+    end
+
+    # Case 1: current first letters identical
+    if x[i] == y[j]
+        return 1 + shortest_common_supersequence(x, y, i+1, j+1)
+    end
+
+    # Case 2: current first letters are not identical: choose shortest supersequence from here.
+
+    # take from x
+    xfirst = 1 + shortest_common_supersequence(x, y, i+1, j)
+    # take from y
+    yfirst = 1 + shortest_common_supersequence(x, y, i, j+1)
+
+    min(xfirst, yfirst)
+end