leetcode 1609 奇偶树
public boolean isEvenOddTree(TreeNode root) {
if (root == null ) return true;
LinkedList<TreeNode> queue = new LinkedList<>();
queue.add(root);
boolean res = true;
boolean level = true;
flag : while (!queue.isEmpty()){
int length = queue.size();
TreeNode item = null;
for (int i=0; i < length;i++){
TreeNode node = queue.poll();
if (node.left != null) queue.add(node.left);
if (node.right != null) queue.add(node.right);
if (level) {
if (node.val % 2 == 0) {
res = false;
break flag;
}
if (item == null){
item = node;
}else if (node.val <= item.val){
res = false;
break flag;
}else {
item = node;
}
}else {
if (node.val % 2 == 1) {
res = false;
break flag;
}
if (item == null){
item = node;
}else if (node.val >= item.val){
res = false;
break flag;
}else {
item = node;
}
}
}
level = !level;
}
return res;
}