UVA.10791 Minimum Sum LCM (唯一分解定理)

UVA.10791 Minimum Sum LCM (唯一分解定理)

题意分析

也是利用唯一分解定理，但是要注意，分解的时候要循环(sqrt(num+1))次，并要对最后的num结果进行判断。

代码总览

#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
#define nmax 505
#define ll long long
using namespace std;
ll n;
int pos = 0;
int main()
{
    //freopen("in.txt","r",stdin);
    int kase = 1;
    while(scanf("%lld",&n) != EOF && n){
        ll temp,sum =0;
        pos = 0;
        int uplimit = floor(sqrt(n + 1));
        bool isin = false;
        for(int i = 2;i<=uplimit;++i){
            isin = false;
            temp = 1;
            if(n % i == 0) pos++;
            while(n%i==0){
                temp*=i;
                n /= i;
                isin = true;
            }
            if(isin) sum+=temp;
            if(n == 1) break;
        }
        if( n != 1 || pos == 0){
            pos++;
            sum += n;
        }
        if(pos == 1) sum++;
        printf("Case %d: %lld\n",kase++,sum);
    }
    return 0;
}