题解 | #32.合并二叉树#

递归

没别的

function mergeTrees( t1 ,  t2 ) {
  if(t2==null)
    return t1;
  if(t1==null)
    return t2;
  //此时t1和t2均不为null
  t1.val += t2.val;
  
  t1.left = mergeTrees(t1.left,t2.left);
  t1.right = mergeTrees(t1.right,t2.right);
  
  return t1;
}
module.exports = {
    mergeTrees : mergeTrees
};