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67 lines
954 B
67 lines
954 B
package validparens
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type stack struct {
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store []rune
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}
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func (s *stack) Push(r rune) {
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s.store = append(s.store, r)
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}
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func (s *stack) Pop() rune {
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res := s.store[len(s.store)-1]
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s.store = s.store[:len(s.store)-1]
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return res
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}
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func (s *stack) Length() int {
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return len(s.store)
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}
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func (s *stack) OnTop(r rune) bool {
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if s.Length() == 0 {
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return false
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}
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return s.store[len(s.store)-1] == r
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}
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func NewStack() stack {
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store := make([]rune, 0)
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return stack{
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store: store,
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}
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}
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func isValid(s string) bool {
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history := NewStack()
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for _, r := range s {
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switch r {
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case '{', '[', '(':
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history.Push(r)
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case ')':
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if !history.OnTop('(') {
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return false
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}
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history.Pop()
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case ']':
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if !history.OnTop('[') {
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return false
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}
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history.Pop()
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case '}':
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if !history.OnTop('{') {
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return false
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}
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history.Pop()
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}
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}
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return history.Length() == 0
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}
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func IsValid(s string) bool {
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return isValid(s)
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}
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