摘要：
题目链接：https://acm.zzuli.edu.cn/zzuliacm/problem.php?cid=1242&pid=4 解法：题中给是求一个等比数列的前n项和取模（1e9+7），已知等比数列前n项求和公式为$s=\frac{a_1(q^n 1)}{q 1}$,现在求前n+1项即可，q== 阅读全文
摘要：
题目链接：http://codeforces.com/contest/839/problem/B cpp include include include include include using namespace std; const int maxn = 100 + 5; int n, k; 阅读全文