fix android build failure

fix include in datasets.cc

attempting fix android build

fix complie err x86

fix ci

fix ci

address review cmmts, fix ci

remove dup code in datasets.cc

stage II tree_adapter

add test case for tree_adapter

use dfs to build tree

add more test case

add test case

fix ci

fix ci round 2

fix ci round 3

fix ci round 4

fix complie error

fix ci round 6

fix ci round 7

fix ci round 8

fix ci round 9