Update all new Tasks

Task/Amb/R/amb-1.r

@@ -0,0 +1,23 @@
+checkSentence <- function(sentence){
+# Input: character vector
+# Output: whether the sentence formed by the elements of the vector is valid
+  for (index in 1:(length(sentence)-1)){
+    first.word  <- sentence[index]
+    second.word <- sentence[index+1]
+
+    last.letter  <- substr(first.word, nchar(first.word), nchar(first.word))
+    first.letter <- substr(second.word, 1, 1)
+
+    if (last.letter != first.letter){ return(FALSE) }
+  }
+  return(TRUE)
+}
+
+amb <- function(sets){
+# Input: list of character vectors containing all sets to consider
+# Output: list of character vectors that are valid
+  all.paths      <- apply(expand.grid(sets), 2, as.character)
+  all.paths.list <- split(all.paths, 1:nrow(all.paths))
+  winners        <- all.paths.list[sapply(all.paths.list, checkSentence)]
+  return(winners)
+}

Task/Amb/R/amb-2.r

@@ -0,0 +1,14 @@
+sentence1 <- c("that", "thing", "grows", "slowly")
+sentence2 <- c("rosetta", "code", "is", "cool")
+sentence  <- list(sentence1, sentence2)
+sapply(sentence, checkSentence)
+[1]  TRUE FALSE
+
+set1 <- c("the", "that", "a")
+set2 <- c("frog", "elephant", "thing")
+set3 <- c("walked", "treaded", "grows")
+set4 <- c("slowly", "quickly")
+sets <- list(set1, set2, set3, set4)
+amb(sets)
+$`26`
+[1] "that"   "thing"  "grows"  "slowly"