摘要：
hdu 1099 Lottery题意：1~n编号的彩票，要买全，等概率条件下平均要买几张。已经买了m张时，买中剩下的概率为1-m/n，则要买的张数为1/(1-m/n)n=2，s=1+1/(1-1/2);n=3，s=1+1/(1-1/3)+1/(1-2/3)s=1+1/(1-1/n)+1/(1-2/n 阅读全文
摘要：
Ignatius's puzzle Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 9859 Accepted Submission(s): 68 阅读全文