A water problem

Problem Description Two planets named Haha and Xixi in the universe and they were created with the universe beginning. There is  73  days in Xixi a year and  137  days in Haha a year.  Now you know the days  N  after Big Bang, you need to answer whether it is the first day in a year about the two planets.   Input There are several test cases(about  5  huge test cases). For each test, we have a line with an only integer  N(0≤N) , the length of  N  is up to  10000000 .   Output For the i-th test case, output Case #i: , then output "YES" or "NO" for the answer.   Sample Input 10001 0 333   Sample Output Case #1: YES Case #2: YES Case #3: NO

这题大家都说是大数，不过他们还说套模板好像不行。然而我不懂什么叫大数。。。我就自己写了一个取余的东西，只要与10001的余数为0就行。

#include <stdio.h> #include <string.h> char a[10000000+10]; int main() { int icase=0; while(~scanf("%s",&a)) { icase++; int len=strlen(a); int b1=10001; int i; int mod1=0; for(i=0; i<len; i++) { mod1=mod1*10+a[i]-'0'; mod1=mod1%b1; } if(mod1==0) printf("Case #%d: YES\n",icase); else printf("Case #%d: NO\n",icase); } return 0; }