sorted sequence 个 1 2 3 5 6 7 conq merge 2 4 5 7 1 2 3 6 merge merge 2 5 4 3 6 merge merge merge merge 回 回 回 3 6 initial sequence5 2 4 7 1 3 2 6 5 2 4 7 1 3 2 6 Divid e Divide further, until… conq uer