Coins HDU - 2844 POJ - 1742 多重背包可行性 当做一般多重背包,二进制优化 #include<cstdio> #include<cstring> int n,m,anss; ],c[],f[]; int main() { int i,j,t; scanf("%d%d",&n,&m); ||m!=) { anss=; memset(f,,sizeof(f)); ;i<=n;i++) scanf("%d&qu…

hdu 2844 poj 1742 Coins 题目相同,但是时限不同,原本上面的多重背包我初始化为0,f[0] = 1;用位或进行优化,f[i]=1表示可以兑成i,0表示不能. 在poj上运行时间正好为时限3000ms....太慢了,hdu直接TLE(时限1s); 之 后发现其实并不是算法的问题,而是库函数的效率没有关注到.我是使用fill()按量初始化的,但是由于memset()可能是系统底层使用了四个字节拷 贝的函数(远比循环初始化快),效率要高得多..这就是为什么一直TLE的原因,fil…

Problem Description Whuacmers use coins.They have coins of value A1,A2,A3...An Silverland dollar. One day Hibix opened purse and found there were some coins. He decided to buy a very nice watch in a nearby shop. He wanted to pay the exact price(witho…

作为一个oier,以及大学acm党背包是必不可少的一部分.好久没做背包类动规了.久违地练习下-.- dd__engi的背包九讲:http://love-oriented.com/pack/ 鸣谢http://blog.csdn.net/eagle_or_snail/article/details/50987044,这里有大部分比较有趣的dp练手题. hud 2602 01背包板子题 #include<cstdio> #include<iostream> #include<cs…

Whuacmers use coins.They have coins of value A1,A2,A3...An Silverland dollar. One day Hibix opened purse and found there were some coins. He decided to buy a very nice watch in a nearby shop. He wanted to pay the exact price(without change) and he kn…

Coins  HDU 2844 不能用最基础的多重背包模板:会超时的!!! 之后看了二进制优化了的多重背包. 就是把多重转变成01背包: 具体思路见:http://www.cnblogs.com/tt123/p/3280521.html #include<iostream> #include<algorithm> #include<stdio.h> #include<string.h> using namespace std; ],a1[],a[],b[];…

HDOJ(HDU).2844 Coins (DP 多重背包+二进制优化) 题意分析 先把每种硬币按照二进制拆分好,然后做01背包即可.需要注意的是本题只需要求解可以凑出几种金钱的价格,而不需要输出种数.因此用0表示不可以,1表示可以.最后对dp数组扫描一遍即可. 代码总览 #include <iostream> #include <cstdio> #include <cstring> #include <algorithm> #define nmax 100…

题目链接:POJ - 1742 题目大意 现有 n 种不同的硬币,每种的面值为 Vi ,数量为 Ni ,问使用这些硬币共能凑出 [1,m] 范围内的多少种面值. 题目分析 使用一种 O(nm) 的 DP (据说这是类多重背包?),枚举每一种硬币,对于每一种硬币 i 枚举每一个面值 j ,如果这个面值 j 使用前 i-1 种硬币已经可以凑出,就直接跳过,否则尝试加入一个硬币 i ,看是否能凑出 j .需要满足 (f[j - Vi] == true) && (UseNum[j - Vi] +…

Coins Time Limit: 3000MS   Memory Limit: 30000K Total Submissions: 33269   Accepted: 11295 Description People in Silverland use coins.They have coins of value A1,A2,A3...An Silverland dollar.One day Tony opened his money-box and found there were some…

Description Aliens on planet Pandora also write computer programs like us. Their programs only consist of capital letters (‘A’ to ‘Z’) which they learned from the Earth. On planet Pandora, hackers make computer virus, so they also have anti-virus sof…