P3092 [USACO13NOV]没有找零No Change 题目描述 Farmer John is at the market to purchase supplies for his farm. He has in his pocket K coins (1 <= K <= 16), each with value in the range 1..100,000,000. FJ would like to make a sequence of N purchases (1 <= N…

[USACO06NOV] Corn Fields (试题来源:Link ) 题目描述 Farmer John has purchased a lush new rectangular pasture composed of \(M\) by \(N (1 ≤ M ≤ 12; 1 ≤ N ≤ 12)\) square parcels. He wants to grow some yummy corn for the cows on a number of squares. Regrettably,…

题目 [USACO14MAR]Counting Friends G 题解 这道题我们可以将 \((n+1)\) 个边依次去掉,然后分别判断去掉后是否能满足.注意到一点, \(n\) 个奶牛的朋友之和必定为偶数,所以去掉的那个数值的奇偶性必定与 \((n+1)\) 个数值之和的奇偶性相同. 接下来很明显的,尽量将朋友多的和朋友多的匹配,所以先从大到小排序,将第一个奶牛和后面的奶牛依次匹配,如果匹配结束,第一个奶牛还有剩余,则此情况必然不可能成立:否则匹配完之后再按照 \(O(n)\) 复杂度的归并…

题目 [USACO14MAR]Sabotage G 题解 本蒟蒻又来了,这道题可以用二分答案来解决.我们可以设答案最小平均产奶量为 \(x \ (x \in[1,10000])\) .然后二分搜索 \(x\) 的最小值. \[\frac{sum-sum[l,r]}{n-(r-l+1)}\leq x \] \[nx-(r-l+1)x\geq sum-sum[l,r] \] \[sum-nx \leq \sum\limits_{i=l}^r{(a[i]-x)} \] 对于如何求 \(\sum\lim…

题目描述 Farmer John is at the market to purchase supplies for his farm. He has in his pocket K coins (1 <= K <= 16), each with value in the range 1..100,000,000. FJ would like to make a sequence of N purchases (1 <= N <= 100,000), where the ith p…

题目描述 Farmer John is at the market to purchase supplies for his farm. He has in his pocket K coins (1 <= K <= 16), each with value in the range 1..100,000,000. FJ would like to make a sequence of N purchases (1 <= N <= 100,000), where the ith p…

题目描述 Farmer John is at the market to purchase supplies for his farm. He has in his pocket K coins (1 <= K <= 16), each with value in the range 1..100,000,000. FJ would like to make a sequence of N purchases (1 <= N <= 100,000), where the ith p…

这个题有点意思,其实不是特别难,但是不太好想...中间用二分找最大的可买长度就行了. 题干: 题目描述 Farmer John <= K <= ), each with value ..,,. FJ would like to make a sequence of N purchases ( <= N <= ,), <= c(i) <= ,). As he makes this sequence of purchases, he can periodically sto…

题目传送门 可能是我退役/NOIP前做的最后一道状压... 题目大意:给你\(k\)个硬币,FJ想按顺序买\(n\)个物品,但是不能找零,问你最后最多剩下多少钱. 注意到\(k<=16\),提示状压.开始设计的状态是\(f[i]\)表示在状态\(i\)下最多剩的钱数,后来发现不好搞因为可能有无解的情况.这种情况我们不妨把状态设计的再"退化"一点,也就是不那么贴近最终的结果,只是一个中间的部分.设\(f[i]\)为在状态\(i\)下,最多能购买的物品数. 因为是按顺序购买的,所以有…

题目 Farmer John has arranged his N \((1 ≤ N ≤ 5,000)\) cows in a row and many of them are facing forward, like good cows. Some of them are facing backward, though, and he needs them all to face forward to make his life perfect. Fortunately, FJ recentl…