65 lines
1.2 KiB
Go
65 lines
1.2 KiB
Go
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package aoc
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type stack[T any] []T
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func NewStack[T any](items ...T) *stack[T] {
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s := make(stack[T], len(items))
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copy(s, items)
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return &s
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}
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// Push adds an element to the top of the stack.
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func (s *stack[T]) Push(v T) {
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*s = append(*s, v)
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}
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// Pop removes the top element from the stack and returns it.
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// If the stack is empty, it panics.
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func (s *stack[T]) Pop() T {
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if s.IsEmpty() {
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var zero T
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return zero
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}
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v := (*s)[len(*s)-1]
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*s = (*s)[:len(*s)-1]
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return v
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}
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// Peek returns the top element from the stack without removing it.
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// If the stack is empty, it panics.
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func (s *stack[T]) Peek() T {
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if s.IsEmpty() {
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var zero T
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return zero
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}
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return (*s)[len(*s)-1]
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}
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// Len returns the number of elements in the stack.
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func (s *stack[T]) Len() int {
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return len(*s)
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}
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// IsEmpty returns true if the stack is empty and false otherwise.
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func (s *stack[T]) IsEmpty() bool {
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return s == nil || len(*s) == 0
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}
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// Clear removes all elements from the stack, returning it to its initial state.
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func (s *stack[T]) Clear() {
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*s = (*s)[:0]
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}
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func (s *stack[T]) Pull() T {
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if s.IsEmpty() {
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var zero T
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return zero
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}
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v := (*s)[0]
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*s = (*s)[1:]
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return v
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}
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