Given a string containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[’ and ‘]’, determine if the input string is valid.
The brackets must close in the correct order, “()” and “()[]{}” are all valid but “(]” and “([)]” are not.
package pack;
import java.util.HashMap;
import java.util.Stack;
class Solution {
public boolean isValid(String s) {
HashMap<Character, Character