Difference between revisions of "2018-2019 Southeastern European Regional Programming Contest (SEERC 2018)"
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Solved by ultmaster. 00:36 (+) | Solved by ultmaster. 00:36 (+) | ||
+ | |||
+ | 题意:平面上有若干个点,每次询问一个底边在 $x$ 轴上的,高为 $l$ 的等腰直角三角形里有几个点。 | ||
+ | |||
+ | 题解:因为 $l$ 不变,记录每个点要被包含的最左位置和最右位置,然后扫描线就好了。 | ||
== Problem F == | == Problem F == |
Revision as of 10:42, 31 October 2018
Problem A
Unsolved. (-5)
题意:问有多少种方法将一个数拆成两个回文数。
题解:写了个暴力 T 飞。
Problem B
Solved by ultmaster. 01:32 (+)
题意:圆周上有 $n$ 个点均匀分布。求有多少三元点对满足能形成一个包含圆心的三角形。
题解:所有方案减去不好的就可以了。答案是 $\displaystyle \frac{n(n-1)(n-2)}{6} - n \sum_{i=0}^{(n-1)/2} i$。
处理 unsigned long long 要用到一点小技巧,把 2 和 3 先除掉。
Problem C
Solved by zerol. 00:53 (+)
Problem E
Solved by ultmaster. 00:36 (+)
题意:平面上有若干个点,每次询问一个底边在 $x$ 轴上的,高为 $l$ 的等腰直角三角形里有几个点。
题解:因为 $l$ 不变,记录每个点要被包含的最左位置和最右位置,然后扫描线就好了。
Problem F
Solved by zerol & kblack. 03:29 (+2)
Problem G
Solved by kblack. 01:21 (+)
Problem I
Solved by kblack. 00:47 (+1)