Codeforces Round 518 (Div. 1) [Thanks, Mail.Ru!]
D
Computer Game
Codeforces
3100
原题
← CE →
翻译中…

Ivan plays some computer game. There are $n$ quests in the game. Each quest can be upgraded once, this increases the reward for its completion. Each quest has $3$ parameters $a_{i}$, $b_{i}$, $p_{i}$: reward for completing quest before upgrade, reward for completing quest after upgrade ($a_{i} \lt b_{i}$) and probability of successful completing the quest.

翻译中…

Each second Ivan can try to complete one quest and he will succeed with probability $p_{i}$. In case of success Ivan will get the reward and opportunity to upgrade any one quest (not necessary the one he just completed). In case of failure he gets nothing. Quests do not vanish after completing.

翻译中…

Ivan has $t$ seconds. He wants to maximize expected value of his total gain after $t$ seconds. Help him to calculate this value.

翻译中…

Input

翻译中…

First line contains $2$ integers $n$ ($ 1 \le n \le 10^{5}$) and $t$ ($ 1 \le t \le 10^{10}$) — number of quests and total time.

翻译中…

Following $n$ lines contain description of quests. Each description is $3$ numbers $a_{i}$ $b_{i}$ $p_{i}$ ($1 \le a_{i} \lt b_{i} \le 10^{8}$, $0 \lt p_{i} \lt 1$) — reward for completing quest before upgrade, reward for completing quest after upgrade and probability of successful completing of quest. $a_{i}$ and $b_{i}$ are integers. All probabilities are given with at most $9$ decimal places.

翻译中…

Output

翻译中…

Print the expected value.

翻译中…

Your answer will be accepted if absolute or relative error does not exceed $10^{-6}$. Formally, let your answer be $a$, and the jury's answer be $b$. Your answer is considered correct if $\frac{|a-b|}{max⁡(b, \,\, 1)} \le 10^{-6}$.

翻译中…

样例

Input #1
3 2
3 1000 0.5
1 2 0.48
3 20 0.3
Output #1
252.2500000000000
InputCopy OutputCopy
Input #2
2 2
1 1000 0.1
2 3 0.2
Output #2
20.7200000000000
InputCopy OutputCopy
题目信息
题号
1067D
时间限制
3 s
内存限制
256 MB
标签
动态规划
贪心
数学
概率论

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。