TimusOJ Bald Spot Revisited(质因数分解)

Posted 2020-10-05 Yuhuger

题目链接http://acm.timus.ru/problem.aspx?space=1&num=1355

莫名其妙地AC了的代码

#include<cstdio>
using namespace std;
const int N=50001;
bool b[N];
int p[N],pnum,t,aa,bb;
void shai(const int &MAX){
    for (int i=2; i<MAX; i++){
        if (!b[i]) p[pnum++]=i;
        for (int j=0; j<pnum&&1ll*p[j]*i<MAX; j++){
            b[i*p[j]]=1;
            if (i%p[j]==0) break;
        }
    }
}
int calc(int x){
    int res=0;
    for (int j=0; j<pnum; j++)
        while (x%p[j]==0){
            x/=p[j];
            ++res;
        }
    if (x>1) ++res;
    return res;
}
int main(){
    scanf("%d",&t);
    shai(N);
    while (t--){
        scanf("%d%d",&aa,&bb);
        if (bb%aa) {puts("0"); continue;}
        else if (aa==bb) {puts("1"); continue;}
        printf("%d\n",calc(bb/aa)+1);
    }
    return 0;
}