96 lines
1.9 KiB
Go
96 lines
1.9 KiB
Go
package collections
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import (
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"sort"
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"sync"
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)
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// OrderedIntSet is a thread-safe sorted set and a stack.
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type OrderedIntSet struct {
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sync.Mutex
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set []int
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}
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// NewOrderedSet returns an initialized OrderedSet
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func NewOrderedIntSet() *OrderedIntSet {
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return &OrderedIntSet{}
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}
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// Push takes an int and adds it to the set. If the elem aready exists, it has no effect.
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func (s *OrderedIntSet) Push(elem int) {
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s.Lock()
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if len(s.set) == 0 {
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s.set = append(s.set, elem)
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s.Unlock()
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return
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}
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// Make sure the list is always sorted
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i := sort.SearchInts(s.set, elem)
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if i < len(s.set) && s.set[i] == elem {
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s.Unlock()
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return
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}
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s.set = append(s.set[:i], append([]int{elem}, s.set[i:]...)...)
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s.Unlock()
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}
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// Pop is an alias to PopFront()
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func (s *OrderedIntSet) Pop() int {
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return s.PopFront()
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}
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// Pop returns the first element from the list and removes it.
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// If the list is empty, it returns 0
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func (s *OrderedIntSet) PopFront() int {
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s.Lock()
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if len(s.set) == 0 {
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s.Unlock()
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return 0
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}
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ret := s.set[0]
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s.set = s.set[1:]
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s.Unlock()
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return ret
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}
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// PullBack retrieve the last element of the list.
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// The element is not removed.
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// If the list is empty, an empty element is returned.
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func (s *OrderedIntSet) PullBack() int {
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s.Lock()
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defer s.Unlock()
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if len(s.set) == 0 {
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return 0
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}
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return s.set[len(s.set)-1]
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}
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// Exists checks if the given element present in the list.
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func (s *OrderedIntSet) Exists(elem int) bool {
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s.Lock()
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if len(s.set) == 0 {
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s.Unlock()
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return false
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}
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i := sort.SearchInts(s.set, elem)
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res := i < len(s.set) && s.set[i] == elem
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s.Unlock()
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return res
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}
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// Remove removes an element from the list.
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// If the element is not found, it has no effect.
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func (s *OrderedIntSet) Remove(elem int) {
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s.Lock()
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if len(s.set) == 0 {
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s.Unlock()
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return
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}
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i := sort.SearchInts(s.set, elem)
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if i < len(s.set) && s.set[i] == elem {
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s.set = append(s.set[:i], s.set[i+1:]...)
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}
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s.Unlock()
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}
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