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###2014-2015 ACM-ICPC, Asia Tokyo Regional Contest - G - Flipping Parentheses 做这个题可以熟悉一下线段树的应用。 首先设'('值为1,')'值为-1,维护一个前缀和,那么字符串平衡的条件便是到任意位置的前缀和都大于0(左括 阅读全文
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###1433F - Zero Remainder Sum $$动态规划,$dp[i][j][p][q]$表示在第$i$行,第$j$列,已经在这一行选取了$p$个元素,且目前的元素和对$k$取模是$q$时的最大和,首先有$dp[1][0][0][0]=0$。可以采用递推的方式由当前状态向下一个状态递 阅读全文
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"A. Orac and Factors" 一个偶数每次操作后都会加2,一个奇数第一次操作后会变成偶数 代码 pragma GCC optimize(2) include include include include include include include include include 阅读全文
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"A. Puzzle Pieces" 首先只有一行或只有一列是可以拼出来的。之后可以猜出剩下的情况只有2x2可以,拼图只有一条边凹进去,构造过程中不难发现这一点。比较简单的写法是判断m+n =mn 代码 pragma GCC optimize(2) include include include i 阅读全文
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"A. Candies" 等比数列求和之后得到k和x的式子,枚举k即可,因为是幂函数,k并不会很大 代码 include include include include include include include include include include include include d 阅读全文
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"A. Ichihime and Triangle" 输出以a c c为三条边的等边三角形即可 代码 include include include include include include include include include include include define INF 阅读全文