错位了.
by VictoriaEVA @ 2023-01-25 22:27:45
@[Victoria_wtq](/user/522483) 6，题目好像没说$m$，$n$是正数吧
by DreamLand_zcb @ 2023-01-25 23:05:12
@[DreamLand_zcb](/user/778011) 说了是非负整数
by VictoriaEVA @ 2023-01-26 18:14:15