Week 147: R solutions

2 files changed, 83 insertions, 0 deletions

diff --git a/challenge-147/abigail/r/ch-1.r b/challenge-147/abigail/r/ch-1.r
new file mode 100644
index 0000000000..ef6dddc678
--- /dev/null
+++ b/challenge-147/abigail/r/ch-1.r
@@ -0,0 +1,46 @@
+#!/usr/local/bin/Rscript
+
+#
+# See https://theweeklychallenge.org/blog/perl-weekly-challenge-147
+#
+
+#
+# Run as: Rscript ch-1.r
+#
+
+suppressPackageStartupMessages (
+    library (gmp)
+)
+
+todo = c (2, 3, 5, 7)
+cat (todo, "")
+
+count = 20 - length (todo)
+
+pow = 10
+while (count > 0 && length (todo) > 0) {
+    new_todo = c ()
+    for (d in 1 : 9) {
+        for (p in todo) {
+            candidate = d * pow + p
+            if (isprime (candidate) > 0) {
+                cat (candidate, "")
+                count = count - 1
+                new_todo = c (new_todo, candidate)
+                if (count <= 0) {
+                    break
+                }
+            }
+            if (count <= 0) {
+                break
+            }
+        }
+        if (count <= 0) {
+            break
+        }
+    }
+    pow = pow * 10
+    todo = new_todo
+}
+
+cat ("\n")
diff --git a/challenge-147/abigail/r/ch-2.r b/challenge-147/abigail/r/ch-2.r
new file mode 100644
index 0000000000..5ae1bf82e5
--- /dev/null
+++ b/challenge-147/abigail/r/ch-2.r
@@ -0,0 +1,37 @@
+#!/usr/local/bin/Rscript
+
+#
+# See https://theweeklychallenge.org/blog/perl-weekly-challenge-147
+#
+
+#
+# Run as: Rscript ch-2.r
+#
+
+suppressPackageStartupMessages (
+    library (hash)
+)
+
+pentagon <- hash ()
+p        <- 0
+n        <- 0
+done     <- FALSE
+
+while (!done) {
+    p <- p + n + n + n + 1
+    n <- n + 1
+    .set (pentagon, p, 1)
+
+    for (seen in keys (pentagon)) {
+        seen <- as.numeric (seen)
+        if (seen + seen <= p &&
+              all (has.key (c (as.character (p - seen),
+                               as.character (p - seen - seen)), pentagon))) {
+            cat (seen, p - seen, "\n")
+            done = TRUE
+        }
+        if (done) {
+            break
+        }
+    }
+}