Online-coding-problems/merge_trees.java at master · JaharshKotha/Online-coding-problems · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    public TreeNode mergeTrees(TreeNode t1, TreeNode t2) {
        ArrayList<String> re = new ArrayList<String>();
        TreeNode r = new TreeNode(t1.val+t2.val);
        help(t1,t2,r,re);

        for(int i=0;i<re.size()-1;i++)
        {
            if(re.get(i)=="null" && re.get(i+1)="null")
            {re.remove(i);re.remove(i+1);}

        }

        return r;

    }

    static void help(TreeNode t1, TreeNode t2 ,TreeNode r,ArrayList<String>re)
    {
        if(t1 ==null && t2==null)
        {
            re.add("null");
            return;
        }
        int v1=0,v2=0;
        if(t1 !=null)
          v1 = t1.val;

        if(t2!=null)
            v2 = t2.val;


        r =new TreeNode(v1+v2);
        int tem = v1+v2;
        re.add(String.valueOf(tem));


        if(t1==null)
            help(t1,t2.left,r.left,re);
        else if(t2==null)
            help(t1.left,t2,r.left,re);
        else
        help(t1.left,t2.left,r.left,re);

        if(t1==null)
            help(t1,t2.right,r.right,re);
        else if(t2==null)
            help(t1.right,t2,r.right,re);
        else
        help(t1.right,t2.right,r.right,re);

    }
}