这题看起来感觉应该不难，但小弟不才看不懂题目的意思
Considering the following rules for sroting a string:
(1)ba->ab
(2)ca->ac
(3)cb->bc
Step by step list how you use the "least-uesd first" conflict resoulution
to complete thesorting for string "cbaca".
麻烦各位大大帮忙解释一下