pid=5105" target="_blank" style="">题目链接:hdu 5105 Math Problem 题目大意:给定a.b,c,d.l,r.表示有一个函数f(x)=|a∗x3+b∗x2+c∗x+d|(L≤x≤R),求函数最大值. 解题思路:考虑极点就可以,将函数求导后得到f′(x)=0的x,即为极值点.在极值点处函数的单调性会发生变化,所以最大值一定就在区间边界和极值点上.注意a=0.b=0的情况,以及极值点不在区间上. #in…

官方题解: f(x)=|a∗x3+b∗x2+c∗x+d|, 求最大值.令g(x)=a∗x3+b∗x2+c∗x+d,f(x)的最大值即为g(x)的正最大值,或者是负最小值.a!=0时, g′(x)=3∗a∗x2+2∗b∗x+c 求出g′(x)的根(若存在,x1,x2,由导数的性质知零点处有极值.ans=max(f(xi)|L≤xi≤R).然后考虑两个端点的特殊性有ans=max(ans,f(L),f(R)). 当时 x = -c/(2*b) 写成 x = -c/2*b 了,然后过pretest了.…

题目链接 大意:给你两个数X,YX,YX,Y,让你找两个数a,ba,ba,b,满足a+b=X,lcm(a,b)=Ya+b=X,lcm(a,b)=Ya+b=X,lcm(a,b)=Y. 思路:枚举gcd(a,b)gcd(a,b)gcd(a,b),假设gcd(a,b)=k,那么a=xa∗k,b=xb∗k,gcd(a,b)=k,那么a=x_a*k,b=x_b*k,gcd(a,b)=k,那么a=xa​∗k,b=xb​∗k,化简上面给的两个式子即可得到 xa+xb=Xk,xa∗xb=Ykx_a+x_b=\f…

P2071 -- A Simple Math Problem IX 时间限制:1000MS      内存限制:262144KB 状态:Accepted      标签:    数学问题-博弈论   无   无 Description 给定a,b,n,保证a≥2,b≥1,a^b≤n.两个人在玩游戏,每个人每次可以把a加1,或者把b加1,但是不能违反a^b<=n,无法再进行操作的人就输掉了这一场游戏. 假设两个人都足够聪明,按照最优策略进行游戏,问先手是否有必胜策略. Input Format 第…

GTY's math problem Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 0    Accepted Submission(s): 0 Problem Description GTY is a GodBull who will get an Au in NOI . To have more time to learn alg…

A Simple Math Problem Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2441    Accepted Submission(s): 1415 Problem Description Lele now is thinking about a simple function f(x). If x < 10 f(x) =…

A Simple Math Problem Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4331    Accepted Submission(s): 2603 Problem Description Lele now is thinking about a simple function f(x).If x < 10 f(x) =…

Jam's math problem Problem Description Jam has a math problem. He just learned factorization.He is trying to factorize ax^2+bx+c into the form of pqx^2+(qk+mp)x+km=(px+k)(qx+m).He could only solve the problem in which p,q,m,k are positive numbers.Ple…

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…

A Simple Math Problem Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2791    Accepted Submission(s): 1659 Problem Description Lele now is thinking about a simple function f(x). If x < 10 f(x) =…