题目DescriptionWhile exploring his many farms, Farmer John has discovered a number of amazing wormholes. A wormhole is very peculiar because it is a one-way path that delivers you to its destination ...
题目DescriptionGeorgia and Bob decide to play a self-invented game. They draw a row of grids on paper, number the grids from left to right by $1$ , $2$ , $3$ , ..., and place $N$ chessmen on differen...