题目链接 求出ai^4+a2^4+......an^4的值, ai为小于n并与n互质的数. 用容斥做, 先求出1^4+2^4+n^4的和的通项公式, 显然是一个5次方程, 然后6个方程6个未知数, 我gauss消元解的(雾 然后筛出n所以的因子, 容斥就好. 容斥的时候, 每一个数的贡献是x^4 * getSum(x), getSum就是上面求出的通项公式. #include <iostream> #include <vector> #include <cstdio>…

The Boss on Mars Problem's Link Mean: 给定一个整数n,求1~n中所有与n互质的数的四次方的和.(1<=n<=1e8) analyse: 看似简单,倘若自己手动推公式的话,还是需要一定的数学基础. 总的思路:先求出sum1=(1^4)+(2^4)+...(n^4),再求出sum2=(1~n中与n不互质的数的四次方的和),answer=sum1-sum2. 如何求sum1呢? 有两种方法: 1.数列差分.由于A={Sn}={a1^4+a2^4+...an^4}…

The Boss on Mars Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1934    Accepted Submission(s): 580 Problem Description On Mars, there is a huge company called ACM (A huge Company on Mars), an…

The Boss on Mars Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1528    Accepted Submission(s): 452 Problem Description On Mars, there is a huge company called ACM (A huge Company on Mars), and…

传送门 The Boss on Mars Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 2462    Accepted Submission(s): 760 Problem Description On Mars, there is a huge company called ACM (A huge Company on Mars)…

The Boss on Mars Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 2494    Accepted Submission(s): 775 Problem Description On Mars, there is a huge company called ACM (A huge Company on Mars), an…

http://acm.hdu.edu.cn/showproblem.php?pid=4059 定义S = 1^4 + 2^4 + 3^4+.....+n^4.如今减去与n互质的数的4次方.问共降低了多少. 容斥原理.能够先把与n不互质的数的4次方求出来.那就先对n进行质因子分解,对质因子的组合运用容斥原理.质因子个数为奇数就加,偶数就减.事实上与求[1,n]内与n互质的数的个数类似,该题重点是计算,防止乘法溢出. 对于求解1^4 + 2^4 + 3^4+.....+n^4,能够先类比1^2+2^…

hdu 5792 要找的无非就是一个上升的仅有两个的序列和一个下降的仅有两个的序列,按照容斥的思想,肯定就是所有的上升的乘以所有的下降的,然后再减去重复的情况. 先用树状数组求出lx[i](在第 i 个数左边的数中比它小的数的个数),ld[i](在第 i 个数左边的数中比它大的数的个数),rx[i](在第 i 个数右边的数中比它小的数的个数) ,rd[i](在第 i 个数右边的数中比它大的数的个数).然后重复的情况无非就是题目中a与c重合(rx[i]*rd[i]),a与d重合(rd[i]*ld[…

A Simple Chess 题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5794 Description There is a n×m board, a chess want to go to the position (n,m) from the position (1,1). The chess is able to go to position (x2,y2) from the position (x1,y1), only and if…

GCD Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4141    Accepted Submission(s): 1441 Problem Description Given 5 integers: a, b, c, d, k, you're to find x in a...b, y in c...d that GCD(x, y)…