you give binary tree root1 root2Imagine cover nod tree overlap you need merge tree new binary tree the merge rule node overlap sum node value new value merge node Otherwise not null node node new treeReturn merge treeNote the merging process start root node tree Example 1input root1 1325 root2 213null4null7output 34554null7example 2input root1 1 root2 12Output 22 ConstraintsThe number nod tree range 0 2000104 Nodeval 104