剑指offer18：树的子结构

/**
* Created by WHZ on 2017/3/31.
*/
public class offer18 {

private class TreeNode{
TreeNode left;
TreeNode right;
int val;
}

boolean HasSubtree(TreeNode pRoot1,TreeNode pRoot2){
boolean result = false;
if(pRoot1!=null&&pRoot2!=null){
if(pRoot1.val==pRoot2.val)
result = DoesTree1HavaTree2(pRoot1,pRoot2);
if(!result)
result = HasSubtree(pRoot1.left,pRoot2);
if(!result)
result = HasSubtree(pRoot1.right,pRoot2);
}
return result;
}

private boolean DoesTree1HavaTree2(TreeNode pRoot1, TreeNode pRoot2) {
if(pRoot2==null) return true;
if(pRoot1==null) return false;
if(pRoot1.val!=pRoot2.val) return false;
return DoesTree1HavaTree2(pRoot1.left,pRoot2.left)
&&DoesTree1HavaTree2(pRoot1.right,pRoot2.right);

}
}