Happy 2004

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Happy 2004


Problem Description
Consider a positive integer X,and let S be the sum of all positive integer divisors of 2004^X. Your job is to determine S modulo 29 (the rest of the division of S by 29).

Take X = 1 for an example. The positive integer divisors of 2004^1 are 1, 2, 3, 4, 6, 12, 167, 334, 501, 668, 1002 and 2004. Therefore S = 4704 and S modulo 29 is equal to 6.
 

Input
The input consists of several test cases. Each test case contains a line with the integer X (1 <= X <= 10000000). 

A test case of X = 0 indicates the end of input, and should not be processed.
 

Output
For each test case, in a separate line, please output the result of S modulo 29.
 

Sample Input
1100000
 

Sample Output
610

2004有三个素因子2,3,167,(还可以看做是一个排列组合题目)


如图所示2004的素因子其实也就是2004的x次方的素因子,对于2004的x次方,ans=(2^0+2^1+2^2.......+2^e1)*(3^0+3^1+3^2+.....+3^e2)*(167^0+167^1+167^2+.......+167^e3)

每个小括号里是每个素因子可能形成的组合,乘起来就是所求的结果(理解不了的试着拆开写写),剩下就是合理运用取余,进行等比数列求和(注意这里要用到取模的逆元或者用二分等比数列求和)

#include<stdio.h>#define M 29#define LL long longLL multi(LL a,LL b){LL res=0;while(b){if(b&1){res=(res+a)%M;}b>>=1;a=(a+a)%M;}return res;}LL pow(LL a,LL b){LL res=1;while(b){if(b&1){res=multi(res,a);}b>>=1;a=multi(a,a);}return res;}int main(){LL x;while(scanf("%lld",&x),x){LL div_2,div_3,div_167;div_2=(pow(2,2*x+1)-1)%M;div_3=(pow(3,x+1)-1)*15%M;div_167=(pow(22,x+1)-1)*18%M;printf("%lld\n",(div_2*div_3*div_167)%M);}return 0;} 


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