Facebook Hacker Cup 2015 Round 1 --- Homework

给一个区间,求该区间内 质因子个数等于k的数 的个数。

暴力预处理一下啦

#include<cstdio>
#include<cstring>
using namespace std;
const int maxn=10000010;
bool pri[maxn];
int cnt[maxn];
void init()
{
    memset(pri,1,sizeof pri);
    memset(cnt,0,sizeof cnt);
    for(int i=2;i<=10000000;i++)
    {
        if(!pri[i]) continue;
        for(int j=i;j<=10000000;j+=i)
        {
            pri[j]=0;
            cnt[j]++;
        }
    }
}
int main()
{
    freopen("homework.txt","r",stdin);
    freopen("outa.txt","w",stdout);
    init();
    int T,l,r,k,i,cas=1;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d%d%d",&l,&r,&k);
        int ans=0;
        for(i=l;i<=r;i++)
            if(cnt[i]==k) ans++;
        printf("Case #%d: %d\n",cas++,ans);
    }
    return 0;
}
时间: 2024-10-13 15:32:30

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