题目
输入两棵二叉树A,B,判断B是不是A的子结构。(ps:我们约定空树不是任意一个树的子结构)
思路
递归思想
在树A中找到和B的根结点的值一样的结点R;
判断树A中以R为根结点的子树是不是包含和树B一样的结点。
代码
/* function TreeNode(x) {
this.val = x;
this.left = null;
this.right = null;
} */
function HasSubtree(pRoot1, pRoot2) {
let res = false;
if (pRoot1 === null || pRoot2 === null) return false;
if (pRoot1.val === pRoot2.val) res = doesTree1HasTree2(pRoot1, pRoot2);
if (!res) res = HasSubtree(pRoot1.left, pRoot2);
if (!res) res = HasSubtree(pRoot1.right, pRoot2);
return res;
}
function doesTree1HasTree2(pRoot1, pRoot2) {
if (pRoot2 === null) return true;
if (pRoot1 === null) return false;
if (pRoot1.val !== pRoot2.val) return false;
return doesTree1HasTree2(pRoot1.left, pRoot2.left) && doesTree1HasTree2(pRoot1.right, pRoot2.right);
}