public static void preOrder(TreeNode root,ArrayList<String> pre){if(root==null){//1:遍历到叶子结点的左右儿子，用#表示空结点pre.add("#");return;}Integer value=root.val;pre.add(value.toString());preOrder(root.left,pre);preOrder(root.right,pre);}public static boolean chkIdentical(TreeNode A, TreeNode B) {ArrayList<String> listA=new ArrayList<String>();ArrayList<String> listB=new ArrayList<String>();//遍历两棵树
        preOrder(A,listA);preOrder(B,listB);//把树的遍历结果转为字符串StringBuilder builderA=new StringBuilder();for(String i:listA){builderA.append(i);}String strA=builderA.toString();StringBuilder builderB=new StringBuilder();for(String j:listB){builderB.append(j);}String strB=builderB.toString();//判断A树序列中是否有B树序列return strA.contains(strB);}

public boolean chkTransform(String A, int lena, String B, int lenb) {if(lena!=lenb){return false;}char[] charsA=A.toCharArray();char[] charsB=B.toCharArray();HashMap<Character,Integer> mapA=new HashMap<Character,Integer>();HashMap<Character,Integer> mapB=new HashMap<Character,Integer>();for(Character ch:charsA){if(mapA.get(ch)==null){mapA.put(ch,1);}else{mapA.put(ch,mapA.get(ch)+1);}}for(Character ch:charsB){if(mapB.get(ch)==null){mapB.put(ch,1);}else{mapB.put(ch,mapB.get(ch)+1);}}        //如果字符种类数不一样，则直接返回falseif(mapA.size()!=mapB.size()){return false;}        //由于不知道具体哪些种类，那么直接取两字符串拼接，遍历拼接后字符串每个字符即可得到两字符串所有种类String sum=A+B;char[] sumchars=sum.toCharArray();for(Character ch:sumchars){if(mapA.get(ch)!=mapB.get(ch)){//无论哪一个字符，只有A，B中数量不相等，则返回falsereturn false;}}return true;}