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我已经找到了高度,然后用k值我正在做postorder来打印元素,但它显示NullPointer异常作为数据不打印。在二叉树中查找K元素
Java代码:
public void kDisplay(int k) {
auxkDisplay(root, k);
}
public void auxkDisplay(TreeNode root1, int k) {
int l = h(root1);
if (l - k == 0)
return;
System.out.print(root1.data + "-");
auxkDisplay(root1.left, k++);
auxkDisplay(root1.right, k++);
}
public int h(TreeNode current) {
TreeNode current1 = current;
if (current1 == null)
return -1;
int l = 1 + h(current1.left);
int r = 1 + h(current1.right);
return Math.max(l, r);
}