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| class Solution {
public boolean isValid(String code) {
int n = code.length(), i = 0;
Deque<String> stack = new ArrayDeque<>();
while (i < n) {
if (code.charAt(i) == '<') {
if (i == n - 1) return false;
if (code.charAt(i + 1) == '/') {
int j = code.indexOf('>', i);
if (j < 0) return false;
String tagName = code.substring(i + 2, j);
if (stack.isEmpty() || !stack.peek().equals(tagName)) return false;
stack.pop();
i = j + 1;
if (stack.isEmpty() && i != n) return false;
} else if (code.charAt(i + 1) == '!') {
if (stack.isEmpty()) return false;
if (i + 9 > n) return false;
String cdata = code.substring(i + 2, i + 9);
if (!"[CDATA[".equals(cdata)) return false;
int j = code.indexOf("]]>", i);
if (j < 0) return false;
i = j + 1;
} else {
int j = code.indexOf('>', i);
if (j < 0) return false;
String tagName = code.substring(i + 1, j);
if (tagName.length() < 1 || tagName.length() > 9) return false;
for (int k = 0; k < tagName.length(); k++) {
if (!Character.isUpperCase(tagName.charAt(k))) return false;
}
stack.push(tagName);
i = j + 1;
}
} else {
if (stack.isEmpty()) return false;
++i;
}
}
return stack.isEmpty();
}
}
|
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