题目:http://poj.org/problem?id=3045 题意:每个牛都有一个wi和si,试将他们排序,每头牛的风险值等于前面所有牛的wj(j<i)之和-si,求风险值最大的牛的最小风险值 分析:这就是noip2012 T2的来源= =只不过这里是加,noip里是乘 不妨设所有牛都按最优顺序排好了,考虑相邻的两头牛i和i+1,如果交换他们的位置,那么对前面和后面的结果都无影响,只是他们两个的风险值变化了(变大了),于是我们可以得到这个时候i和i+1的关系 设w1+w2+...+wi-1…

题目: poj3045 Cow Acrobats 解析: 贪心题,类似于国王游戏 考虑两个相邻的牛\(i\),\(j\) 设他们上面的牛的重量一共为\(sum\) 把\(i\)放在上面,危险值分别为\(x_1=sum-s_i\),$ x_2=sum+w_i-s_j$ 把\(j\)放在上面,危险值分别为\(x_3=sum-s_j\), \(x_4=sum+w_j-s_i\) 若把j放在上面更优,则有\(max(x_3,x_4)<max(x_1,x_2)\) 有四种情况 \(x_3<x_1\) \…

POJ 3045 Cow Acrobats 这是个贪心的题目,和网上的很多题解略有不同,我的贪心是从最下层开始,每次找到能使该层的牛的风险最小的方案, 记录风险值,上移一层,继续贪心. 最后从遍历每一层的风险值,找到其中的最大值 我一开始对sum-p[i].a-p[i].b从小到大排序,这样第一次取出的就是能使最下层的牛的风险最小的方案,在上移一层时,这一层的风险值   为sum-p[i].a-p[i].b-p[0].a,由于p[0].a是固定值,所以第二次直接取出的就是能使该层的牛的风险最小的…

Cow Acrobats Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 4998   Accepted: 1892 Description Farmer John's N (1 <= N <= 50,000) cows (numbered 1..N) are planning to run away and join the circus. Their hoofed feet prevent them from tig…

Cow Acrobats Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 3686   Accepted: 1428 Description Farmer John's N (1 <= N <= 50,000) cows (numbered 1..N) are planning to run away and join the circus. Their hoofed feet prevent them from tig…

题目链接:http://poj.org/problem?id=3045 Cow Acrobats Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 5713   Accepted: 2151 Description Farmer John's N (1 <= N <= 50,000) cows (numbered 1..N) are planning to run away and join the circus. The…

Description Farmer John's N (1 <= N <= 50,000) cows (numbered 1..N) are planning to run away and join the circus. Their hoofed feet prevent them from tightrope walking and swinging from the trapeze (and their last attempt at firing a cow out of a ca…

题目链接:http://begin.lydsy.com/JudgeOnline/problem.php?id=1332 题意: 有n头牛在“叠罗汉”. 第i头牛的体重为w[i],力量为s[i]. 一头牛的压扁程度 = 它上面所有牛的体重之和 - s[i] 所有牛的总压扁程度 = 所有牛中最大的那个压扁程度 问你总压扁程度最小为多少. 题解: 贪心. 套路: 选取最小的一个单元——相邻的两头牛,进行贪心策略的局部证明. 贪心策略: 假设最左边为顶部,最右边为底部. 从左往右分别编号0...n-1.…

https://vjudge.net/problem/POJ-3045 读题后提取到一点:例如对最底层的牛来说,它的崩溃风险=所有牛的重量-(底层牛的w+s),则w+s越大,越在底层. 注意范围lb=-INF. #include<iostream> #include<cstdio> #include<queue> #include<cstring> #include<algorithm> #include<cmath> #includ…

题意 Farmer John's N (1 <= N <= 50,000) cows (numbered 1..N) are planning to run away and join the circus. Their hoofed feet prevent them from tightrope walking and swinging from the trapeze (and their last attempt at firing a cow out of a cannon met…