Rearrange the linked list in zig zag way
function zigZag ( node , flag ) { if ( node == null node . next == null ) { return node ; } if ( flag == 0 ) { if ( node . data > node . next . data ) { swap ( node , node . next ) ; } return zigZag ( node . next , 1 ) ; } else { if ( node . data < node . next . data ) { swap ( node , node . next ) ; } return zigZag ( node . next , 0 ) ; } }