/*ID: qq104801LANG: C++TASK: fact4*/#include <iostream>#include <fstream>#include <cstring>#include <vector>#include <map>#include <list>#include <set>#include <queue>#include <cstdio>#include <algorithm>#include <cmath>using namespace std;void test(){        freopen("fact4.in","r",stdin);    freopen("fact4.out","w",stdout);    int n;    cin>>n;    int m=1,pp=100000,f;    for(int i=1;i<=n;i++)    {        f=i%pp;        m*=f;        while(m%10==0)            m/=10;        while(m/pp>0)            m%=pp;    }    cout<<m%10<<endl; }int main () {            test();            return 0;}

USACO TrainingGrader Results     8 users onlineCHN/2 DNK/1 GRC/1 IND/1 SGP/1 TUR/1 USA/1USER: cn tom [qq104801]TASK: fact4LANG: C++Compiling...Compile: OKExecuting...   Test 1: TEST OK [0.005 secs, 3372 KB]   Test 2: TEST OK [0.005 secs, 3372 KB]   Test 3: TEST OK [0.005 secs, 3372 KB]   Test 4: TEST OK [0.005 secs, 3372 KB]   Test 5: TEST OK [0.008 secs, 3372 KB]   Test 6: TEST OK [0.005 secs, 3372 KB]   Test 7: TEST OK [0.011 secs, 3372 KB]   Test 8: TEST OK [0.008 secs, 3372 KB]   Test 9: TEST OK [0.008 secs, 3372 KB]   Test 10: TEST OK [0.008 secs, 3372 KB]All tests OK.YOUR PROGRAM (‘fact4‘) WORKED FIRST TIME! That‘s fantastic -- and a rare thing. Please accept these special automated congratulations.Here are the test data inputs:------- test 1 ----1------- test 2 ----2------- test 3 ----7------- test 4 ----14------- test 5 ----143------- test 6 ----645------- test 7 ----777------- test 8 ----888------- test 9 ----999------- test 10 ----1000Keep up the good work!Thanks for your submission!