tju_virus的专栏

题意：给4个数n，r，k，m，求从n中选r个数（至少间隔k ）并将这r个数分成至多m组一共有多少种情况。 输入为5 2 3 2时 Sample input means you can choose 1 and 4,1 and 5,2 and 5 in the same day. And you can make the machines in the same group or in th