I cannot solve this problem http://icpc.njust.edu.cn/Contest/194/Problem/F
I used to solve another problem http://lightoj.com/volume_showproblem.php?problem=1132 which requires me to determinate the sum of 1^k+2^k+3^k+........+n^k (n<=10^15,k<=50) I mananged to set a matrix related to binomial coefficients, but I don't know if it is helpful for the http://icpc.njust.edu.cn/Contest/194/Problem/F .