原题下载 USACO2015FEB-G3 答案 (Analysis by Nick Wu) Sort the haybales by location. Consider two haybales i and j such that Bessie can start somewhere between those haybales and break through all th...
原题下载 USACO2015OPEN-G2 答案 (Analysis by Nick Wu) This is a DP problem where we iteratively count the number of palindromes that we can build from the middle. Let f(a,r1,r2) be the number of pal...
原题下载 USACO2015OPEN-G1 答案 (Analysis by Steven Hao) We first present a naive algorithm that recursively iterates through all nodes. Below is Python code implementing this naive algorithm, which...
原题下载 USACO2015OPEN-S3 答案 (Analysis by Nick Wu) Start by sorting the patches of the grass in increasing order of quality. Let f(i) be the maximum energy that we can accumulate if we end at pat...
原题下载 USACO2015OPEN-S2 答案 (Analysis by Nick Wu). If we pick a bale that we want to add hay to, then we can guarantee that Bessie cannot break through that bale. Therefore, once we have picked ...
原题下载 USACO2015OPEN-S1 答案 (Analysis by Nick Wu) There are 5007 different combinations to check, which is far too many. However, just like with the bronze version of this problem, where we were...
原题下载 USACO2015OPEN-B4 答案 (Analysis by Nick Wu) Our first thought is to try all possible paths that Bessie can take. For small N, this works out well, but it turns out that for a grid of size ...
原题下载 USACO2015OPEN-B2 答案 (Analysis by Nick Wu) In a pure brute-force solution, we would try every possible combination of assignments of variables to values. There are 7 variables, with at mo...
原题下载 USACO2015OPEN-B3 答案 (Analysis by Nick Wu) The NN hay bales define N−1N−1 intervals that Bessie can be inside. Let's consider answering for a given interval, whether Bessie can escape if ...
