Problem 1901 Period II Accept: 107    Submit: 297 Time Limit: 1000 mSec    Memory Limit : 32768 KB  Problem Description For each prefix with length P of a given string S,if S[i]=S[i+P] for i

Problem 2129 子序列个数 Accept: 147    Submit: 432 Time Limit: 2000 mSec    Memory Limit : 32768 KB  Problem Description 子序列的定义：对于一个序列a=a[1],a[2],......a[n]。则非空序列a'=a[p1],a[p2]......a[pm]为a的一个子