tasks a-s

Task/Priority-queue/R/priority-queue-1.r

@@ -0,0 +1,27 @@
+PriorityQueue <- function() {
+  keys <<- values <<- NULL
+  insert <- function(key, value) {
+    temp <- c(keys, key)
+    ord <- order(temp)
+    keys <<- temp[ord]
+    values <<- c(values, list(value))[ord]
+  }
+  pop <- function() {
+    head <- values[[1]]
+    values <<- values[-1]
+    keys <<- keys[-1]
+    return(head)
+  }
+  empty <- function() length(keys) == 0
+  list(insert = insert, pop = pop, empty = empty)
+}
+
+pq <- PriorityQueue()
+pq$insert(3, "Clear drains")
+pq$insert(4, "Feed cat")
+pq$insert(5, "Make tea")
+pq$insert(1, "Solve RC tasks")
+pq$insert(2, "Tax return")
+while(!pq$empty()) {
+  print(pq$pop())
+}

Task/Priority-queue/R/priority-queue-2.r

@@ -0,0 +1,5 @@
+[1] "Solve RC tasks"
+[1] "Tax return"
+[1] "Clear drains"
+[1] "Feed cat"
+[1] "Make tea"

Task/Priority-queue/R/priority-queue-3.r

@@ -0,0 +1,18 @@
+PriorityQueue <-
+  setRefClass("PriorityQueue",
+              fields = list(keys = "numeric", values = "list"),
+              methods = list(
+                insert = function(key,value) {
+                  temp <- c(keys,key)
+                  ord <- order(temp)
+                  keys <<- temp[ord]
+                  values <<- c(values,list(value))[ord]
+                },
+                pop = function() {
+                  head <- values[[1]]
+                  keys <<- keys[-1]
+                  values <<- values[-1]
+                  return(head)
+                },
+                empty = function() length(keys) == 0
+                ))

Task/Priority-queue/R/priority-queue-4.r

@@ -0,0 +1 @@
+pq <- PriorityQueue$new()