[题解]284E. Coin Troubles(dp+图论建模) 题意就是要你跑一个完全背包,但是要求背包的方案中有个数相对大小的限制 考虑一个\(c_i<c_j\)的限制,就是一个\(c_i\)一定可以对应一个\(c_j\),一个常见的钦定手法是,直接把\(c_j\)的权值捆绑在\(c_i\)上,实现选一个\(c_i\)必选一个\(c_j\).但是题目里是大于号怎么办,那就直接在背包中钦定先拿一个\(c_j\)即可. 现在问题就是维护这一个捆绑的关系,我们可以直接根据差分约束的那种方法建模出来…

Link \(\text{Solution:}\) 菜鸡自己想出来了状态设计,但是没有实现出来--菜死了 设\(dp[i][j]\)表示该选第\(i\)个,最多选\(j\)个的最优解.注意这里的定义仅仅是最优解,而不是先手最优. 那么,对于每一个\(dp[i][j]\)都要由下一步的\(dp[i+x][x+x]\)转移而来.注意的是,每一步的先后手不一样.所以轮到对方的时候要用剩下的石子数减去对方的最优解.因为对方选的最优,同时意味着我们在那部分也是最优的,一减就是了. 于是,我们可以枚举起点,…

这道题目其实就是说有N张纸牌,问至少连续K张正面朝上的可能性是多少. 可以用递推做.首先我们将题目所求从 至少K张 转化为 总数 - 至多K张 (为什么要这样自己想) 设F[i][j]为前i个纸牌至多K张的种数.其中j记录第i张纸牌的状态,1为正面朝上,0为反面. 那么可以总结出 f[i][] = f[i - ][] + f[i - ][]; f[i][] = f[i - ][] + f[i - ][]; ] -= ; ] -= f[i - k][]; 最后要记住这道题需要写高精,我第一次就是这…

题目描述 Farmer John's cows like to play coin games so FJ has invented with a new two-player coin game called Xoinc for them. Initially a stack of N (5 <= N <= 2,000) coins sits on the ground; coin i from the top has integer value C_i (1 <= C_i <=…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2069 Problem Description Suppose there are 5 types of coins: 50-cent, 25-cent, 10-cent, 5-cent, and 1-cent. We want to make changes with these coins for a given amount of money.For example, if we have 11…

SP5271 XOINC - A Coin Game 双倍经验:P2964 [USACO09NOV]硬币的游戏A Coin Game O3做法(TLE):枚举i,j,k,即剩下i枚金币,上一轮选了j枚金币,这一轮选k(1<=k<=j * 2)枚金币. O2做法 1:容易发现,对于[j-1],k枚举范围为1~2j-2:对于[j],k的范围只增加了2j-1,2j两项,可以枚举i,j,再由[j-1]的状态继续判断2j-1,2j两项(sum为前缀和) #include<bits/stdc++.h…

题目描述 Farmer John's cows like to play coin games so FJ has invented with a new two-player coin game called Xoinc for them. Initially a stack of N (5 <= N <= 2,000) coins sits on the ground; coin i from the top has integer value C_i (1 <= C_i <=…

https://daniu.luogu.org/problemnew/show/P2964 dp[i][j] 表示桌面上还剩i枚硬币时,上一次取走了j个的最大得分 枚举这一次要拿k个,转移到dp[i-k][k] dp[i][j]=max(sum[i]-dp[i-k][k]) 因为 上一次取走j个和取走j-1个 k的取值范围 只相差 2*j-1 和 2*j 所以 直接 dp[i][j]=dp[i][j-1] 然后k分别等于  2*j-1 和 2*j,转移 最后输出dp[n][1],因为先手可以拿1…

题意:n颗硬币 两个人从前往后按顺序拿 如果上一个人拿了i颗 那么下一个可以拿1-2*i颗 问先手能获得的最大收益 题解:比较典型的最大最小最大最小..DP了 但是暴力做的话是n^3 所以就体现出了这个题的巧妙之处  dp[i][j]表示拿到了第i颗上一个人拿了j颗 dp[i][j]由 dp[i + k][k] k = 1,2...2 * j转移来 dp[i][j - 1]由 dp[i + k][k] k = 1,2...2 * (j - 1)转移来 有许多状态是一样的 所以dp[i][j-1]…

题目描述 Farmer John's cows like to play coin games so FJ has invented with a new two-player coin game called Xoinc for them. Initially a stack of N (5 <= N <= 2,000) coins sits on the ground; coin i from the top has integer value C_i (1 <= C_i <=…

题目描述 Farmer John's cows like to play coin games so FJ has invented with a new two-player coin game called Xoinc for them. Initially a stack of N (5 <= N <= 2,000) coins sits on the ground; coin i from the top has integer value C_i (1 <= C_i <=…

题面 题解 将路径连边\((x, y, d)\) ,将航线连边\((x, y, d - w)\).其中线路是从\(x\)到\(y\),航线的费用为\(w\),\(d\)的含义如题面. 跑一遍\(SPFA\)最长路即可. 注意判断负环的情况,此时要输出\(-1\). 代码 #include <iostream> #include <cstdio> #include <cstdlib> #include <cstring> #include <algori…

题目 Coins Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 12330 Accepted Submission(s): 4922 Problem Description Whuacmers use coins.They have coins of value A1,A2,A3-An Silverland dollar. One day H…

原题链接在这里:https://leetcode.com/problems/coin-change/ 题目: You are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you need to make up that amount. If that amount of m…

题意:给出1,5,10,25,50五种硬币,再给出n,问有多少种不同的方案能够凑齐n 自己写的时候写出来方案数老是更少(用的一维的) 后来搜题解发现,要用二维的来写 http://blog.csdn.net/keshuai19940722/article/details/11025971 这一篇说的是会有面值的重复问题,还不是很理解 还有就是一个预处理的问题, 看了题解之后再自己写,很习惯的把处理dp数组写到while循环里面,一直tle 后来看到这篇题解 http://www.cnblogs.…

目录 题目链接 题解 题目链接 luogu P2962 [USACO09NOV]灯Lights 题解 可以折半搜索 map合并 复杂度 2^(n / 2)*logn 高斯消元后得到每个点的翻转状态 爆搜自由元得到最优翻转状态 // luogu-judger-enable-o2 #include<map> #include<queue> #include<cstdio> #include<cstring> #include<algorithm> u…

刷题备忘录,for bug-free 招行面试题--求无序数组最长连续序列的长度,这里连续指的是值连续--间隔为1,并不是数值的位置连续 问题: 给出一个未排序的整数数组,找出最长的连续元素序列的长度. 如: 给出[100, 4, 200, 1, 3, 2], 最长的连续元素序列是[1, 2, 3, 4].返回它的长度:4. 你的算法必须有O(n)的时间复杂度 . 解法: 初始思路 要找连续的元素,第一反应一般是先把数组排序.但悲剧的是题目中明确要求了O(n)的时间复杂度,要做一次排序,是不能达…

突然很想刷刷题,LeetCode是一个不错的选择,忽略了输入输出,更好的突出了算法,省去了不少时间. dalao们发现了任何错误,或是代码无法通过,或是有更好的解法,或是有任何疑问和建议的话,可以在对应的随笔下面评论区留言,我会及时处理,在此谢过了. 过程或许会很漫长,也很痛苦,慢慢来吧. 编号 题名 过题率 难度 1 Two Sum 0.376 Easy 2 Add Two Numbers 0.285 Medium 3 Longest Substring Without Repeating C…

洛谷 1938  [USACO09NOV]找工就业Job Hunt 题目描述 Bessie is running out of money and is searching for jobs. Farmer John knows this and wants the cows to travel around so he has imposed a rule that his cows can only make D (1 <= D <= 1,000) dollars in a city be…

题目链接: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=1269 10328 - Coin Toss Time limit: 3.000 seconds 问题描述 Toss is an important part of any event. When everything becomes equal toss is the ultim…

题目链接:Coin on the Table 一开始想用DFS做的,做了好久都超时. 看了题解才明白要用动态规划. 设置一个三维数组dp,其中dp[i][j][k]表示在时间k到达(i,j)所需要做的最小改动,那么递推式如下: 图片来源:Editorial,其中当从周围的格子可以直接移动到(i,j)时,delta=0:否则,需要改变周围格子的方向符号,delta=1. 即k-1时刻在(i,.j)周围的四个格子,然后在k时刻移动到(i,j).并且,看这四个格子中的方向符号是否直接可以完成这次移动,…

相关链接: noip2018总结 noip2017是我见过的有史以来最坑爹的一场考试了. 今年北京市考点有一个是我们学校,我还恰好被分到了自己学校(还是自己天天上课的那个教室),于是我同时报了普及提高,一天半的时间都考了. 这次考试总的来说基本上都爆炸了.虽然都拿了一等奖,但这根本不能说明问题,从中可以看出我在敲代码学习上还是问题百出. 下面我分两篇来总结一个kubi的OIer的解题思路及心得,当然包括正解.然而我莫名其妙的打了好长好长……难道我太勤奋了? OIer常识:本文所有log均以2为底…

Problem Description People in Silverland use square coins. Not only they have square shapes but also their values are square numbers. Coins with values of all square numbers up to 289 (=17^2), i.e., 1-credit coins, 4-credit coins, 9-credit coins, ...…

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1851 Accepted Submission(s): 1065 Problem Description After hh has learned how to play Nim game, he begins to try another coin game which seems much…

Time Limit: 6000/3000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 677 Accepted Submission(s): 321 Problem Description We know that Daizhenyang is chasing a girlfriend. As we all know, whenever you chase a beautiful…

Bob has a not even coin, every time he tosses the coin, the probability that the coin's front face up is \frac{q}{p}(\frac{q}{p} \le \frac{1}{2})​p​​q​​(​p​​q​​≤​2​​1​​). The question is, when Bob tosses the coin kktimes, what's the probability that…

Canonical Coin Systems 题目描述 A coin system S is a finite (nonempty) set of distinct positive integers corresponding to coin values, also called denominations, in a real or imagined monetary system. For example, the coin system in common use in Canada…

2019 杭电多校 9 1006 题目链接:HDU 6685 比赛链接:2019 Multi-University Training Contest 9 Problem Description Rikka hates coins, and she used to never carry any coins with her. These days, Rikka is doing her summer internship abroad. Without mobile payment, Rikka…

描述 Farmer John's cows like to play coin games so FJ has invented with a new two-player coin game called Xoinc for them. Initially a stack of N (5 ≤ N ≤ 2,000) coins sits on the ground; coin i from the top has integer value Ci (1 ≤ Ci ≤ 100,000). The…

题目 A Communist regime is trying to redistribute wealth in a village. They have have decided to sit everyone around a circular table. First, everyone has converted all of their properties to coins of equal value, such that the total number of coins is…