new files

Task/Balanced-brackets/R/balanced-brackets-1.r

@@ -0,0 +1,5 @@
+balanced <- function(str){
+  str <- strsplit(str, "")[[1]]
+  str <- ifelse(str=='[', 1, -1)
+  all(cumsum(str) >= 0) && sum(str) == 0
+}

Task/Balanced-brackets/R/balanced-brackets-2.r

@@ -0,0 +1,3 @@
+balanced <- function(str) {
+  regexpr('^(\\[(?1)*\\])*$', str, perl=TRUE) > -1
+}

Task/Balanced-brackets/R/balanced-brackets-3.r

@@ -0,0 +1,6 @@
+rand.parens <- function(n) paste(permute(c(rep('[',n),rep(']',n))),collapse="")
+
+as.data.frame(within(list(), {
+  parens <- replicate(10, rand.parens(sample.int(10,size=1)))
+  balanced <- sapply(parens, balanced)
+}))

Task/Balanced-brackets/R/balanced-brackets-4.r

@@ -0,0 +1,11 @@
+   balanced             parens
+1     FALSE               ][][
+2     FALSE [][[]]][[]][]]][[[
+3     FALSE     ][[][][]][][[]
+4     FALSE     ][][][][][][][
+5      TRUE [[[][]]][[[][][]]]
+6      TRUE                 []
+7     FALSE           ]][[][[]
+8     FALSE     []]]][[[]][[[]
+9      TRUE     [[[[][[][]]]]]
+10     TRUE                 []