package main

func isValid(s string) bool {
	mapping := map[byte]byte{
		')': '(',
		'}': '{',
		']': '[',
	}
	stack := make([]byte, 0)
	for i := 0; i < len(s); i++ {
		if v, ok := mapping[s[i]]; !ok {
			stack = append(stack, s[i])
		} else {
			if len(stack) == 0 || stack[len(stack)-1] != v {
				return false
			} else {
				stack = stack[:len(stack)-1]
			}
		}
	}

	return len(stack) == 0
}