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path: root/go/bracket-push/bracket_push.go
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package brackets

const testVersion = 3

type Stack []rune

func (s *Stack) Push(r rune) {
	*s = append(*s, r)
}

func (s *Stack) Pop() (r rune) {
	r, *s = (*s)[len(*s)-1], (*s)[:len(*s)-1]
	return
}

func (s *Stack) Len() int {
	return len(*s)
}

func Bracket(s string) (bool, error) {
	var st Stack
	pair := map[rune]rune{
		'}': '{',
		']': '[',
		')': '(',
	}
	for _, v := range s {
		switch v {
		case '{', '[', '(':
			st.Push(v)
		case '}', ']', ')':
			if st.Len() == 0 {
				return false, nil
			}
			if r := st.Pop(); r != pair[v] {
				return false, nil
			}
		}
	}
	return st.Len() == 0, nil
}