Function to merge given two binary trees
static Node MergeTrees ( Node t1 , Node t2 ) { if ( t1 == null ) return t2 ; if ( t2 == null ) return t1 ; Stack < snode > s = new Stack < > ( ) ; snode temp = new snode ( ) ; temp . l = t1 ; temp . r = t2 ; s . add ( temp ) ; snode n ; while ( ! s . isEmpty ( ) ) { n = s . peek ( ) ; s . pop ( ) ; if ( n . l == null n . r == null ) continue ; n . l . data += n . r . data ; if ( n . l . left == null ) n . l . left = n . r . left ; else { snode t = new snode ( ) ; t . l = n . l . left ; t . r = n . r . left ; s . add ( t ) ; } if ( n . l . right == null ) n . l . right = n . r . right ; else { snode t = new snode ( ) ; t . l = n . l . right ; t . r = n . r . right ; s . add ( t ) ; } } return t1 ; }