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题目描述： 有一个无限大的矩形，初始时你在左上角（即第一行第一列），每次你都可以选择一个右下方格子，并瞬移过去（如从下图中的红色格子能直接瞬移到蓝色格子），求到第n行第m列的格子有几种方案，答案对1000000007取模。 Input Output Input示例 Output示例 阅读全文
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Description Beside other services, ACM helps companies to clearly state their “corporate identity”, which includes company logo but also other signs, 阅读全文
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题目描述: Given two strings a and b we define a*b to be their concatenation. For example, if a = "abc" and b = "def" then a*b = "abcdef". If we think of c 阅读全文
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Description String analysis often arises in applications from biology and chemistry, such as the study of DNA and protein molecules. One interesting p 阅读全文
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题目大意：有n张钞票，面值可能不同。你要买一件东西，可能需要找零钱。问最少付多少钱，并求出最少的钞票张数。 题目分析：定义状态dp(i,w)表示前i张钞票凑成w元需要的最少钞票张数。则状态转移方程为dp(i,w)=min(dp(i-1,w),dp(i-1,w-a(i))+1)。其中a(i)为第i张钞 阅读全文
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Description Given a string, find a substring of it which the original string contains exactly n such substrings. Description Given a string, find a su 阅读全文
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Description Given two strings, you have to tell the length of the Longest Common Substring of them. For example: str1 = banana str2 = cianaic So the L 阅读全文
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Rescue the Rabbit Time Limit: 20000/10000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2036 Accepted Submission(s): 阅读全文
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Description Great! Your new software is almost finished! The only thing left to do is archiving all your n resource files into a big one. Wait a minut 阅读全文
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题目大意:给出的m个字符串都有一个权值。用小写字母构造一个长度不超过n的字符串S，如果S包含子串s，则S获取s的权值。输出具有最大权值的最小字符串S。 题目分析:先建立AC自动机。定义状态dp(step，u)表示长度为step、在u节点上的最大权值。状态转移方程为:dp(step，u)=max(dp 阅读全文