Leetcode #20 | #Easy | [[Стек]] | [[Хэш-таблицы]]
## Идея
Стек
## [[Big-O]]
- Время ```O(N)```
- Память  ```O(N)```
## Код
```Java
class Solution {
    public boolean isValid(String s) {
        Map<Character, Character> map = Map.of(')', '(', ']', '[', '}', '{');
        Deque<Character> stack = new ArrayDeque<>();
        for (char c : s.toCharArray()) {
            if (map.containsKey(c)) {
                if (stack.isEmpty() || stack.pop() != map.get(c)) return false;
            } else stack.push(c);
        }
        return stack.isEmpty();
    }
}
```