摘要：
2020-2021 ACM-ICPC Brazil Subregional Programming Contest A Sticker Album 概率递推, fi 表示得到 i 张贴纸要开包数的期望 则当 a > 0 时, 1~a, fi = 1(开一包至少 a 张贴纸) i > a, 则 \(f 阅读全文
摘要：
Codeforces Round #699 (Div. 2) A Space Navigation int main() { IOS; for (cin >> _; _; --_) { int x, y; cin >> x >> y; string s; cin >> s; for (auto c 阅读全文