> After solving this problem,I can't help admitting that DP is a world which fully fill with amazement，from the simple one dimension DP,to two dimension DP even to staue DP,tree DP,DP problem is just like a kaleidoscope. But the further reflection reveal that it is always the same because of the similar essence.in my eyes,every DP problem has a (mostly two dimension)table and a equation bewteen two states.If we can controll the table and the relationship between every states,we can conque the problem completely.