Priority queue: Difference between revisions

insert.orderord <- findInterval(key, keys)

keys <<- append(keys, key, insert.orderord)

values <<- append(values, value, insert.orderord)

head <- list(key=keys[1],value=values[[1]])

printwith(pq$pop(), cat(key,":",value,"\n"))

}</lang>With output:<lang R>[1] ": Solve RC tasks"

[1]2 : "Tax return"

[1]3 : "Clear drains"

[1]4 : "Feed cat"

[1]5 : "Make tea"</lang>A similar implementation using R5 classes:<lang R>PriorityQueue <-

setRefClass("PriorityQueue",

fields = list(keys = "numeric", values = "list"),

methods = list(

insert = function(key,value) {

insert.order <- findInterval(key, keys)

keys <<- append(keys, key, insert.order)

values <<- append(values, value, insert.order)

},

pop = function() {

head <- list(key=keys[1],value=values[[1]])

keys <<- keys[-1]

values <<- values[-1]

return(head)

},

empty = function() length(keys) == 0

))</lang>The only change in the example would be in the instantiation:<lang R>pq <- PriorityQueue$new()</lang>.