leetcode/HasSubTree.java at master · actor168/leetcode · GitHub

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importjava.util.ArrayList;

classHasSubTree {

publicstaticvoidmain(String[] args) {
TreeNoderoot1 = newTreeNode(8);
root1.right = newTreeNode(8);
root1.right.right = newTreeNode(9);
root1.right.right.right = newTreeNode(2);
root1.right.right.right.right = newTreeNode(5);

TreeNoderoot2 = newTreeNode(8);
root2.right = newTreeNode(9);
root2.right.left= newTreeNode(3);
root2.right.right = newTreeNode(2);

System.out.println(newHasSubTree().hasSubtree(root2, root1));
	}


publicbooleanhasSubtree(TreeNoderoot1,TreeNoderoot2) {
ArrayList<TreeNode> l1 = newArrayList<>();
ArrayList<TreeNode> l2 = newArrayList<>();

traverse(l1, root1);
traverse(l2, root2);

if (l1.size() == 0 || l2.size() == 0) returnfalse;
if (l1.size() == l2.size()) returnequals(root1, root2) || equals(root2, root1);

if (l1.size() < l2.size()) {// 判断 root1 是 root2的子树
for(TreeNodet : l2) {
if (t.val == l1.get(0).val){ // 开始迭代遍历
booleanres = equals(t, l1.get(0));
if (res) returntrue;
 }
 }
returnfalse;
 } else { // 判断 root2 是 root1 的子树
for(TreeNodet : l1) {
if (t.val == l2.get(0).val){ // 开始迭代遍历
booleanres = equals(l2.get(0), t);
if (res) returntrue;
 }
 }
returnfalse;
 }
 }

voidtraverse(ArrayList<TreeNode> list, TreeNoderoot) {
if (root == null) return;
list.add(root);
traverse(list, root.left);
traverse(list, root.right);
 }

booleanequals(TreeNodea, TreeNodeb) {
if (a == null && null == b) returntrue;
if (a == null) returnfalse;
if (b == null) returntrue;
if (a.val == b.val) {
returnequals(a.left, b.left) && equals(a.right, b.right);
 }
returnfalse;
 }
}