Difference between revisions of "ACM-ICPC 2018 Qingdao Online Contest"
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Solved by kblack. 01:04 (+) | Solved by kblack. 01:04 (+) | ||
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| + | 题意：周期性按按钮，求亮着的情况按下的次数。 | ||
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| + | 题解：周期 $a \times c$，周期只有 $a+c$ 个关键点，周期内乘系数再加上最后一段。 | ||
== Problem K == | == Problem K == | ||
Revision as of 11:00, 16 September 2018
ECNU Foreigners
ultmaster: 题目比较。。正常的比赛。
Problem A
Solved by zerol. 00:12 (+)
温暖的签到。
Problem B
Solved by ultmaster. 02:14 (+)
题意：给一棵黑白树，定义白节点代价为 0，黑节点代价为到最近的白节点祖先的距离。每次询问一个点集，允许修改一个黑节点为白节点，求点集中代价最大的东西的最小值。
题解：二分答案，然后求超过答案的部分的 LCA。然后将这个点染白，检查超过答案的部分是不是被卡进答案范围内了。
Problem C
Solved by zerol. 00:35 (+)
题意：给一些指令，问是否有限步内结束。
题解：状态数很少，直接模拟，如果遇到重复状态就不停机了。
Problem D
Solved by kblack. 04:10 (+4)
Problem E
Problem F
Unsolved. 04:59 (-5)
Problem G
Solved by zerol. 02:50 (+)
题意：给一个数列，每次删除其中一个数，求出每一段的逆序对数量的最大值。强制在线。
题解：考虑新分裂出的两段，短的那段暴力计算，长的那段把短的那段以及删除掉的数的贡献从中扣除，复杂度 $O(n \log^2 n)$。
zerol: 自闭了近两小时，两度做成另一道题，所以根本过不了样例。背锅
Problem H
Solved by ultmaster. 00:55 (+)
题意：直线上红绿灯每秒变换，求所有点对的旅行代价。
题解：应该瞎 DP 一下就好了。奇偶搞错了自闭了好一会儿。
Problem I
Problem J
Solved by kblack. 01:04 (+)
题意：周期性按按钮，求亮着的情况按下的次数。
题解：周期 $a \times c$，周期只有 $a+c$ 个关键点，周期内乘系数再加上最后一段。
Problem K
Solved by kblack. 00:14 (+)
温暖的签到。
One,Two,Three,AK
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Problem B
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Problem C
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Problem D
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Problem F
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Problem G
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Problem H
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Problem I
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Problem K
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