我试了一下,它适用于左子树,但不适用于右子树。
我很接近,但我的逻辑是错误的,任何人都可以帮助纠正并解释这个逻辑。
public static MyNode preOrderNumbering(MyNode n) {
if (n != null) {
n.obj = 0; // Set root decoration to 0;
preOrderHelper(n, 1); // Set decorations according to preorder.
}
return n;
}
public static MyNode preOrderHelper(MyNode n, int counter) {
if (n != null) {
if (n.left != null) {
n.left.obj = counter++; // Set the left object decoration to current count + 1;
preOrderHelper(n.left, counter);
}
if (n.right != null) {
n.right.obj = counter++; // Set the left object decoration to current count + 1;
preOrderHelper(n.right, counter);
}
}
return n;
}
前:
后: