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| class Solution {
public boolean isValid(String s) {
if ((s.length() & 1) != 0) {
return false;
}
Stack<Character> stack = new Stack<>();
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
switch (c) {
case '(':
case '{':
case '[':
stack.push(c);
break;
case ')':
if (stack.isEmpty() || stack.pop() != '(') {
return false;
}
break;
case '}':
if (stack.isEmpty() || stack.pop() != '{') {
return false;
}
break;
case ']':
if (stack.isEmpty() || stack.pop() != '[') {
return false;
}
break;
default:
throw new IllegalArgumentException("Unsupported char: " + c);
}
}
return stack.isEmpty();
}
}
|