题目链接: http://www.lightoj.com/volume_showproblem.php?problem=1235 题目描述: 给出n个硬币,每种硬币最多使用两次,问能否组成K面值? 解题思路: 因为K草鸡大,尽管n很小,但是2^n很大,无法用背包做到O(nK)的复杂度.如果暴力枚举复杂度立马飙升到O(2^(n+1)).··········· 所以引进一种新的算法,折半查找:把所要枚举的值,先把前部分的值所有情况枚举出来,再把后部分的值所有情况枚举出来并排序,结合二分进行查找. 这…

题目链接:http://www.lightoj.com/volume_showproblem.php?problem=1235 题意: 有N个硬币(N<=18).问是否能在每一个硬币使用不超过两次的情况下支付正好K的面额. 思路 : dfs构造出用这些硬币用前一半能支付的全部费用和后一半能支付的全部费用. 之后排序,枚举前一半的每一个面值在第二个里面二分寻找就可以.(或者用set保存). 代码:(set) #include <stdio.h> #include <ctime>…

1235 - Coin Change (IV)    PDF (English) Statistics Forum Time Limit: 1 second(s) Memory Limit: 32 MB Given n coins, values of them are A1, A2 ... An respectively, you have to find whether you can pay K using the coins. You can use any coin at most t…

Coin Change (IV) Time Limit: 1000MS   Memory Limit: 32768KB   64bit IO Format: %lld & %llu [Submit]   [Go Back]   [Status] Description Given n coins, values of them are A1, A2 ... An respectively, you have to find whether you can pay K using the coin…

题目链接: Lightoj  1231 - Coin Change (I) 题目描述: 就是有n种硬币,每种硬币有两个属性(价值,数目).问用给定的硬币组成K面值,有多少种方案? 解题思路: 赤果果的多重背包,简单搞一下就好了.席八!烦烦烦.今天绝对是出门刷提前没看黄历,刚开始套了一个多重背包板子,蓝而跑出来的答案并不对,改来改去就错在细节的地方. #include <cmath> #include <cstdio> #include <cstring> #includ…

题目链接: http://www.lightoj.com/volume_showproblem.php?problem=1076 题目描述: 给出n个数,要求分成m段,问这m段中最大的总和,最小是多少? 解题思路: 二分每一段的长度,然后判定枚举长度是否合法. 刚看到这个题目就想到了dp,但是dp的复杂度还是很高的,然后就一直放着,放着....学了折半枚举,拿起来一看,哇塞,简直惊喜啊! #include<cstdio> #include<cstring> #include<…

先上题目: 1231 - Coin Change (I)   PDF (English) Statistics Forum Time Limit: 1 second(s) Memory Limit: 32 MB In a strange shop there are n types of coins of value A1, A2 ... An. C1, C2, ... Cn denote the number of coins of value A1, A2 ... An respective…

先上题目: 1232 - Coin Change (II)   PDF (English) Statistics Forum Time Limit: 1 second(s) Memory Limit: 32 MB In a strange shop there are n types of coins of value A1, A2 ... An. You have to find the number of ways you can make K using the coins. You ca…

题目链接: http://www.lightoj.com/volume_showproblem.php?problem=1170 题目描述: 给出一些满足完美性质的一列数(x > 1 and y > 1 such that m = xy.) 然后给出一个区间,问在这个区间中的完美数组成的搜索二叉树的个数是多少?解题思路: 1,打标算出所有的完美数列中的数字 2,打表算出卡特兰数列,等着以后用 3,卡特兰数列递推式:F[N] = F[N-1] * ( 4 * N - 2 ) / ( N + 1…

C - Coin Change (III) Time Limit:2000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Submit Status Practice LightOJ 1233 Description In a strange shop there are n types of coins of value A1, A2 ... An. C1, C2, ... Cn denote the number of…

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 money cannot be made up by any combination of the coins,…

Coin Change Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 10289    Accepted Submission(s): 3451 Problem Description Suppose there are 5 types of coins: 50-cent, 25-cent, 10-cent, 5-cent, and 1…

Load Balancing 给出每个学生的学分.   将学生按学分分成四组,使得sigma (sumi-n/4)最小.         算法:   折半枚举 #include <iostream> #include <cstdio> #include <cstring> #include <cmath> #include <algorithm> #include <string> #include <vector> #i…

1514: Packs Time Limit: 10 Sec  Memory Limit: 128 MBSubmit: 61  Solved: 4[Submit][Status][Web Board] Description Give you n packs, each of it has a value v and a weight w. Now you should find some packs, and the total of these value is max, total of…

Coin Change Time Limit: 1000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 10924 Accepted Submission(s): 3669 Problem Description Suppose there are 5 types of coins: 50-cent, 25-cent, 10-cent, 5-cent, and 1-cent…

这道题乍一看是普通的01背包,最最基础的,但是仔细一看数据,发现普通的根本没法做,仔细观察数组发现n比较小,利用这个特点将它划分为前半部分和后半部分这样就好了,当时在网上找题解,找不到,后来在挑战程序设计上找到了这个题,就拿来引用一下 挑选物品的方法总从2^n中,直接枚举肯定不行,因为n最大为40,但是如果n为20就可以了,这时候就要用到折半枚举,先枚举前一半,在枚举后一半.先把前把部分的选取方法对应的重量和价值总和记为w1, v1,这样后半部分寻找w2 <= W - w1时 使v2最大的选取方…

UVA 674  Coin Change  解题报告 题目链接:http://acm.hust.edu.cn/vjudge/contest/view.action?cid=87730#problem/E 题目: 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 o…

JSU省赛队员选拔赛个人赛1 一.题目概述: A.Coin Change(暴力求解.动态规划)     B.Fibbonacci Number(递推求解) C.Max Num(排序.比较) D.单词数(字符串比较.库函数运用) E.无限的路(平面几何) F.叠筐(规律输出) 二.解题报告: A.Coin Change 给一个钱的总金额,求出用100个以内的50分.25分.10分.5分.1分硬币拼成该金额的不同拼法. 直接暴力,打表什么的都是浮云.开始总觉得用暴力求解显得自己没风度,不够高端霸气上…

                                                           Coin Change (II) Time Limit: 1000MS   Memory Limit: 32768KB   64bit IO Format: %lld & %llu [Submit]   [Go Back]   [Status] Description In a strange shop there are n types of coins of value A1…

You are given coins of different denominations and a total amount of money. Write a function to compute the number of combinations that make up that amount. You may assume that you have infinite number of each kind of coin. Note: You can assume that…

888E - Maximum Subsequence 思路:折半枚举. 代码: #include<bits/stdc++.h> using namespace std; #define ll long long #define pb push_back #define mem(a,b) memset(a,b,sizeof(a)) ; int a[N]; set<int>s; int main() { ios::sync_with_stdio(false); cin.tie(); i…

题目链接:Prime Gift 题意: 给出了n(1<=n<=16)个互不相同的质数pi(2<=pi<=100),现在要求第k大个约数全在所给质数集的数.(保证这个数不超过1e18) 题解: 如果暴力dfs的话肯定超时间,其实给的n数据范围最大是16是一个很奇妙的数(一般折半枚举基本上是这样的数据范围@.@-).所以想到折半枚举,把所有的质数分成两份求出每份中所有小于1e18的满足条件的数.然后二分答案,写cheak函数时遍历第一个集合,对第二个集合二分(折半枚举基本上这个套路).…

题目大意 给定N(N<=35)个数字,每个数字都<= 2^15. 其中一个或多个数字加和可以得到s,求出s的绝对值的最小值,并给出当s取绝对值最小值时,需要加和的数字的个数. 题目分析 需要枚举集合的所有情况,2^35,会超时.考虑使用折半枚举的方法,考虑前 N/2个数字构成的集合S1,在S1中进行所有情况枚举,复杂度为 2^17,并将所有可能的和sum以及构成和sum需要的数字个数count存放在map M中:然后在S2中进行所有情况的枚举,复杂度为2^17,对于每种情况的sum2,在M中查…

SubsetTime Limit: 30000MS        Memory Limit: 65536KTotal Submissions: 6754        Accepted: 1277 DescriptionGiven a list of N integers with absolute values no larger than 1015, find a non empty subset of these numbers which minimizes the absolute v…

Subset Time Limit: 30000MS   Memory Limit: 65536K Total Submissions: 5721   Accepted: 1083 Description Given a list of N integers with absolute values no larger than 1015, find a non empty subset of these numbers which minimizes the absolute value of…

UVA.674 Coin Change (DP) 题意分析 有5种硬币, 面值分别为1.5.10.25.50,现在给出金额,问可以用多少种方式组成该面值. 每种硬币的数量是无限的.典型完全背包. 状态转移方程 dp[j+c[i]] = dp[j] + dp[j+c[i]] 代码总览 /* Title:UVA.674 Author:pengwill Date:2017-2-16 */ #include <iostream> #include <cstdio> #include <…

题意 给定一个包含\(n\)个数的序列\(a\),在其中任选若干个数,使得他们的和对\(m\)取模后最大.(\(n\leq 35\)) 题解 显然,\(2^n\)的暴枚是不现实的...,于是我们想到了折半枚举,分成两部分暴枚,然后考虑合并,合并的时候用two-pointers思想扫一遍就行了. 其实这是一道折半枚举+Two-Pointers的很好的练手题 //最近CodeForces有点萎,可能会JudgementError,但已经评测过了,能AC,多交几次应该可以 #include <cstd…

题意:有n杯盐溶液,给定每杯里面盐的质量以及盐溶液的质量.问你有多少种方案选择一个子集,使得集合里面的盐溶液倒到一个被子里面以后,浓度为A/B. 折半枚举,暴力搜索分界线一侧的答案数,跨越分界线的答案,一侧用map存下来,枚举另一侧去统计. #include<cstdio> #include<map> using namespace std; typedef long long ll; ll ans; int n,a,b,m[39],t[39]; map<ll,int>…

Description A square is a 4-sided polygon whose sides have equal length and adjacent sides form 90-degree angles. It is also a polygon such that rotating about its centre by 90 degrees gives the same polygon. It is not the only polygon with the latte…

Description Consider equations having the following form: a1x13+ a2x23+ a3x33+ a4x43+ a5x53=0 The coefficients are given integers from the interval [-50,50]. It is consider a solution a system (x1, x2, x3, x4, x5) that verifies the equation, xi∈[-50,…