Update README.md

1 files changed, 14 insertions, 2 deletions

diff --git a/challenge-117/james-smith/README.md b/challenge-117/james-smith/README.md
index aa4a62c493..84b19d8bef 100644
--- a/challenge-117/james-smith/README.md
+++ b/challenge-117/james-smith/README.md
@@ -72,8 +72,14 @@ sub schroder_cache_array {
 }
 ```
 
-But as we've said before recursion is a curse - so to remove the function
-overhead of recursion we can re-write this like this:
+But as we've said before recursion is a curse - but we notice that
+```
+  T0,m = 1                          
+  Tn,0 = Tn-1,0 + Tn-1,1
+  Tn,m = Tn-1,m + Tn-1,m+1 + Tn,m-1
+```
+We can use that to define each row of a triangle with `Sn` as the last
+value.
 
 ```perl
 sub schroder_non_recursive {
@@ -88,6 +94,12 @@ sub schroder_non_recursive {
 }
 ```
 
+We again use the row "flip" as we only need one row and the previous
+one to get values...
+
+There is a faster solution - in that the Scrhoder numbers can be
+written as a recurrence relation:
+
 ```perl
 sub schroder_recurrence_rel {
   my( $size, @S ) = ( shift, 1, 2 );