摘要：a[i]=a[i 1]+b[i 1]+1, b[i]=2 a[i 1] 5 ; a[1]=1,b[1]=1, 问a[x]=?,b[x]=? 很简单的递推，一步步推即可，但是，如果x是10^9，如何推？ 思维：递推式可以化为矩阵乘积 那么，矩阵A[i]=A[i 1] B; A[i+1]=A[i] B= 阅读全文

摘要：Jzzhu has invented a kind of sequences, they meet the following property: You are given x and y, please calculate fn modulo 1000000007 (109 + 7). Inpu 阅读全文