public class MergeTwoTrees {
static class TreeNode {
int val = 0;
TreeNode left = null;
TreeNode right = null;
}
/**
*
* @param t1 TreeNode類
* @param t2 TreeNode類
* @return TreeNode類
*/
public TreeNode mergeTrees (TreeNode t1, TreeNode t2) {
// write code here
//總體思想(遞歸):以t1為根本,将t2拼接到t1中,具體分一下幾種情況:
//(1)t1不為空,t2為空
//(2)t1為空,t2不為空
//(3)t1與t2都不為空
if (t1 == null && t2 == null)
return null;
//(1)t1不為空,t2為空
if(t1!=null && t2 == null){
return t1;
}
//(2)t1為空,t2不為空
if(t1==null && t2!=null){
return t2;
}
//(3)t1與t2都不為空
if(t1 != null && t2 != null){
t1.val += t2.val;//合并資料
t1.left = mergeTrees(t1.left,t2.left);//遞歸左子樹
t1.right = mergeTrees(t1.right,t2.right);//遞歸右子樹
}
return t1;
}
public static void main(String[] args) {
}
}