Uva10780 (decomposition prime factor)

High precision can be directly used for brute force.

You can also choose not to use high precision:

Decompose m into a prime factor and record each factor and its number of times. Then, calculate the number of occurrences of each factor in the factorial of N, and divide the number by the number of occurrences in m, which is the possible K value. Obtain the minimum K.

#include<iostream>#include<cstdio>#include<cstdlib>#include<cstring>#include<cmath>#include<map>#include<set>#include<vector>#include<algorithm>#include<stack>#include<queue>using namespace std;#define INF 1000000000#define eps 1e-8#define pii pair<int,int>#define LL long long intint m,n,k,T;int prime[5005],vis[5005];void getprime(){    int num=0;    for(int i=2;i<5000;i++)    {        if(vis[i]==0) prime[num++]=i;        for(int j=i*i;j<5000;j+=i)        {            if(j%i==0) vis[j]=1;        }    }}int main(){    //freopen("in6.txt","r",stdin);    //freopen("out.txt","w",stdout);    getprime();    scanf("%d",&T);    for(int cas=1;cas<=T;cas++)    {        scanf("%d%d",&m,&n);        k=INF;        vector<pii>zhi;        for(int i=0;prime[i]<=m;i++)        {            int num=0;            while(m%prime[i]==0)            {                num++;                m/=prime[i];            }            if(num)            zhi.push_back(make_pair(prime[i],num));        }        for(unsigned int i=0;i<zhi.size();i++)        {            int t=zhi[i].first,num=0;            for(int j=n;j>=1;j--)            {                int jj=j;                while(jj%t==0)                {                    num++;                    jj/=t;                }            }            //cout<<‘k‘<<num<<endl;            k=min(k,num/(zhi[i].second));        }        printf("Case %d:\n",cas);        if(k)        printf("%d\n",k);        else            printf("Impossible to divide\n");    }    //fclose(stdin);    //fclose(stdout);    return 0;}

 

Uva10780 (decomposition prime factor)