已知n条二次曲线si(x) = ai*x^2 + bi*x + ci(ai ≥ 0),定义F(x) = max{si(x)},求出F(x)在[0,1000]上的最小值. 链接:传送门 分析:最大值最小,我们可以利用二分来解,但是有一个更牛的方法叫:“三分法”,这个方法的应用范围是凸函数,可以看一个图像: L和R是边界,m1,m2是三等分点,如果f(m1) < f(m2),那么最小值肯定在[l,m2]内,注意,不是[l,m1]因为如果m1在最低点右边,那么就会矛盾,同理,如果f(m2) < f(…

F - Error Curves Time Limit:3000MS     Memory Limit:0KB     64bit IO Format:%lld & %llu Description Josephina is a clever girl and addicted to Machine Learning recently. She pays much attention to a method called Linear Discriminant Analysis, which h…

Josephina is a clever girl and addicted to Machine Learning recently. She pays much attention to a method called Linear Discriminant Analysis, which has many interesting properties. In order to test the algorithm's efficiency, she collects many datas…

Josephina is a clever girl and addicted to Machine Learning recently. She pays much attention to a method called Linear Discriminant Analysis, which has many interesting properties. In order to test the algorithm's efficiency, she collects many datas…

Problem Description Josephina is a clever girl and addicted to Machine Learning recently. She pays much attention to a method called Linear Discriminant Analysis, which has many interesting properties. In order to test the algorithm's efficiency, she…

Error Curves Time Limit:3000MS    Memory Limit:0KB    64bit IO Format:%lld & %llu SubmitStatusPracticeUVALive 5009 Appoint description: Description Josephina is a clever girl and addicted to Machine Learning recently. She pays much attention to a met…

Error Curves Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 1198    Accepted Submission(s): 460 Problem Description Josephina is a clever girl and addicted to Machine Learning recently. She pa…

Error Curves Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 4137    Accepted Submission(s): 1549 Problem Description Josephina is a clever girl and addicted to Machine Learning recently. Shepay…

题目传送门 /* 三分:凹(凸)函数求极值 */ #include <cstdio> #include <algorithm> #include <cstring> #include <cmath> using namespace std; ; const int INF = 0x3f3f3f3f; const double EPS = 0.0000000001; struct F { double a, b, c; }f[MAXN]; int n; dou…

UVA 1476 1476 - Error Curves 题目链接 题意:给几条下凹二次函数曲线.然后问[0,1000]全部位置中,每一个位置的值为曲线中最大值的值,问全部位置的最小值是多少 思路:三分法,因为都是下凹函数,所以全部曲线合并起来.仍然是一个下凹函数.满足单峰.用三分求极值 代码: #include <cstdio> #include <cstring> #include <cmath> #include <algorithm> using n…