题目大意:一个鞋匠,有n只鞋要修,修某只鞋的时间ti已知,某只鞋晚修一天要交的罚款fi也已知.现在让找个修鞋顺序使得罚款最少. 题目分析:本来想水一下这道题,没想到真的AC啦.后来又查的题解,找的解释.一个比较能说服我的解释是这样的:这个鞋匠不管怎样都要赔本,他每修一只鞋能降低的最大损失是fi/ti,只需要按fi/ti从大到小的顺序来修即可. 代码如下: # include<iostream> # include<cstdio> # include<cstring> #…

链接:http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=967 描述:要做n双鞋子,第 i 双鞋子要做Ti天,每天消耗Si的钱(当前正在做第 i 双鞋子时不耗钱).求在最少消耗钱的情况下做鞋子的顺序. 思路:贪心 明显是一个排序的模型,然后我们就思考顺序怎么确定.考虑当前两双鞋子a和b,它们的顺序对它们前后的鞋子都没有影响,它们所创造的影响仅仅…

题意:鞋匠一口气接到了不少生意,但是做鞋需要时间,鞋匠只能一双一双地做,根据协议每笔生意如果拖延了要罚钱. 给出每笔生意需要的天数和每天的罚钱数,求出最小罚钱的排列顺序. 只要按罚款/天数去从大到小排序,如果比例一样就按序号排序(要求字典序). 解释我就不献丑了,附上Staginner大神的证明: 对于为什么贪心策略是这个样子的,我们不妨拿相邻的两个事件a.b来说明一下.由于a.b之后的事件是固定的,所以我们无论排成ab还是排成ba后面部分的损失都是固定的,那么损失的差别主要来源于究竟是排成ab…

题目连接:10026 Shoemaker's Problem 题目大意:有一个鞋匠接了n双要修的鞋子, 修每双鞋需要d天,每推迟一天修将亏损val元,问按什么样的顺序修鞋可以保证损失最少,如果有多种情况输出字典序最小的. 解题思路:最开始把损失钱数最大的放在前面,后来发现每层子问题是相互有影响的,所以不能从整体的损失来看,所以后来改成对两个鞋的装态比较,只要考虑哪双鞋放前和哪双鞋放后就可以了. #include <stdio.h> #include <string.h> #incl…

题目链接:  http://acm.hust.edu.cn/vjudge/contest/view.action?cid=68990#problem/K 题目需求:鞋匠有n个任务,第i个任务要花费ti天,同时第i个任务每耽误一天要有fi的罚金.求完成所有任务的最小罚金. 题目解析: 这题看了题解,解法如下: 这个是一个贪心的题目首先按照fine/time降序排列,值相同的再按序号升序排列. 对于为什么贪心策略是这个样子的,我们不妨拿相邻的两个事件a.b来说明一下.由于a.b之后的事件是固定的,所…

/* * UVA_10026.cpp * * Created on: 2013年10月10日 * Author: Administrator */ #include <iostream> #include <cstdio> #include <algorithm> using namespace std; const int maxn = 1010; struct job{ double a; int num; }p[maxn]; bool cmp(job x, job…

题意:鞋匠现在有n个工作要做,每个工作要x天,没延迟一天需要付款y,鞋匠每天只能做一个工作,问使得鞋匠最少赔款的工作顺序. 思路:工作和工作之间排序,如果a.value*b.day>b.value*a.day  a工作应该排在前面 #include <iostream> #include<cstdio> #include<algorithm> using namespace std; #define N 1010 struct node{ int day; int…

B. Clique Problem time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The clique problem is one of the most well-known NP-complete problems. Under some simplification it can be formulated as f…

题目链接: B. Andrey and Problem time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Andrey needs one more problem to conduct a programming contest. He has n friends who are always willing to help.…

Bob and math problem Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 401    Accepted Submission(s): 149 Problem Description Recently, Bob has been thinking about a math problem.There are N Digit…

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=967 对价钱与天数比例排序,贪心即可. #include <cstdio> #include <cstring> #include <algorithm> #define maxn 2000 using namespace std; int n; struc…

HDU 4974 A simple water problem pid=4974" target="_blank" style="">题目链接 签到题,非常easy贪心得到答案是(sum + 1) / 2和ai最大值的最大值 代码: #include <cstdio> #include <cstring> #include <algorithm> using namespace std; const int N =…

D. Dasha and Very Difficult Problem 题目连接: http://codeforces.com/contest/761/problem/D Description Dasha logged into the system and began to solve problems. One of them is as follows: Given two sequences a and b of length n each you need to write a se…

B. Clique Problem time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The clique problem is one of the most well-known NP-complete problems. Under some simplification it can be formulated as f…

An Easy Problem Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 8333   Accepted: 4986 Description As we known, data stored in the computers is in binary form. The problem we discuss now is about the positive integers and its binary form.…

题目链接 Dasha and Very Difficult Problem 求出ci的取值范围,按ci排名从小到大贪心即可. 需要注意的是,当当前的ci不满足在这个取值范围内的时候,判为无解. #include <bits/stdc++.h> using namespace std; #define rep(i,a,b) for(int i(a); i <= (b); ++i) + ; int a[N], b[N], c[N], op[N]; int l, r, L, R, cnt; b…

传送门 D. Clique Problem time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The clique problem is one of the most well-known NP-complete problems. Under some simplification it can be formulated…

题目链接: Ugly Problem Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 363    Accepted Submission(s): 134Special Judge Problem Description Everyone hates ugly problems.You are given a positive integ…

题目链接:http://codeforces.com/problemset/problem/798/C 题意:给你n个数,a1,a2,....an.要使得gcd(a1,a2,....an)>1,可以执行一次操作使ai,ai+1变为ai - ai + 1, ai + ai + 1.求出使得gcd(a1,a2,....an)>1所需要的最小操作数. 解题思路:首先,要知道如果能够实现gcd(a1,a2,....an)>1,那么a1~an肯定都是偶数(0也是偶数),所以我们的目的就是用最少的操…

题目链接: B. Clique Problem time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The clique problem is one of the most well-known NP-complete problems. Under some simplification it can be formulate…

描述As we known, data stored in the computers is in binary form. The problem we discuss now is about the positive integers and its binary form. Given a positive integer I, you task is to find out an integer J, which is the minimum integer greater than…

题目链接:http://codeforces.com/contest/761/problem/D D. Dasha and Very Difficult Problem time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Dasha logged into the system and began to solve problem…

题意: 给定n<=1000个小兵,A每次都能使小兵掉1点血,B每次能使所有小兵掉1点血,A.B轮流攻击,每次轮到A他会选择是否攻击,轮到B必须攻击.求A最多能杀死多少小兵.(当小兵血量为1时被攻击到视为被杀死) 思路: 如果所有小兵血量都不一样,A必定能杀死所有小兵.如果有小兵血量相同,那么A必定会攻击一些小兵使他们血量不同.所以我们可以把A的攻击分为两类:用来刚好杀死小兵的一次, 和用来使小兵血量不同的攻击. 我们可以用贪心的思想预处理出怎样用最小的攻击次数让小兵的血量都不同. 然后我们可以用…

D. Yet Another Monster Killing Problem You play a computer game. In this game, you lead a party of…

数轴上有n 个点,第i 个点的坐标为xi,权值为wi.两个点i,j之间存在一条边当且仅当 abs(xi-xj)>=wi+wj. 你需要求出这张图的最大团的点数. Solution 把每个点看作以 \((x_i,0)\) 为圆心,半径为 \(r_i\) 的圆 那么如果不相交就有边相连 干脆看作线段吧,所以就是求最大不相交线段数 这就是一个很基础的贪心,以右端点为第一关键字,左端点为第二关键字 sort 然后"能取就取"即可 #include <bits/stdc++.h>…

题意 题目链接 给出一棵树,每个节点有权值,选出\(k\)个联通块,最大化 \[\frac{\sum_{i \in S} a_i}{k}\] Sol 结论:选出的\(k\)个联通块的大小是一样的且都等于最大联通块的大小 证明:因为我们是在保证分数最大的情况下才去最大化\(k\),一个很经典的结论是单独选择一个权值最大的联通块得到的分数一定是最大的,然后我们这时我们才去考虑最大化\(k\) 那么思路就很清晰了,先一遍dfs dp出最大联通块,然后再一遍dfs从下往上删就行了 #include<bi…

Description Famil Door wants to celebrate his birthday with his friends from Far Far Away. He has n friends and each of them can come to the party in a specific range of days of the year from ai to bi. Of course, Famil Door wants to have as many frie…

题中只有两个条件:任意区间异或值不等于0或m. 如果只考虑区间异或值不等于 0,则任意两个前缀异或值不能相等. 而除了不能相等之外,还需保证不能出现任意两个前缀异或值不等于m. 即 $xor[i]$^$xor[j]!=m$, $\Rightarrow$ m^xor[j] 这个异或前缀就不可以再次出现了. 用一个数组标记一下就好了~ #include <bits/stdc++.h> #define N 1000000 #define setIO(s) freopen(s".in&quo…

Shoemaker's Problem Shoemaker has N jobs (orders from customers) which he must make. Shoemaker can work on only one job in each day. For each ith job, it is known the integer Ti (1<=Ti<=1000), the time in days it takes the shoemaker to finish the jo…

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