buildTaskTree <- function (taskList) {
  form <- list()
  for (tid in taskList) {
    path <- strsplit(tid,"/")[[1]]
    ## Trim CAF name and task name
    path <- path[5:(length(path)-1)]
    form <- buildTaskTreeAux(form,path,tid) 
  }
  form
}

buildTaskTreeAux <- function (set,path,tid) {
  if (length(path) ==1) {
    set[[path]] <- c(set[[path]],tid)
  } else {
    sub <- path[1]
    subset <- set[[sub]]
    if (is.null(subset)) {
      subset <- list()
    }
    set[[sub]] <- buildTaskTreeAux(subset,path[2:length(path)],tid) 
  }
  set
}

splitTaskTree <- function (tt) {
  result <- list(formA=character(),formB=character(),remainder=character())
  splitTaskTreeAux(tt,result)
}

splitTaskTreeAux <- function (tt,result) {
  if(is.character(tt)) {
    n <- length(tt)
    if (n %% 2 > 0) {
      ## Take care of remainder
      m <- sample(n,1)
      result$remainder <- c(result$remainder,tt[m])
      tt <- tt[-m]
      n <- n-1
    }
    if (n>0) {
      m <- sample(n,n/2)
      result$formA <- c(result$formA,tt[m])
      result$formB <- c(result$formB,tt[-m])
    }
  } else {
    for (sub in tt) {
      result <- splitTaskTreeAux(sub,result)
    }
    rem <- result$remainder
    result$remainder <- character()
    result <- splitTaskTreeAux(rem,result)
  }
  result
}