SDNU 1427.分解质因数（水题）

#include <cstdio>
#include <iostream>
#include <cmath>
#include <string>
#include <cstring>
#include <algorithm>
#include <queue>
#include <vector>
#include <map>
using namespace std;
#define ll long long
const int inf = 0x3f3f3f3f;
const int mod = 1e9+7;

int a, b, tot, pri[10000+8], en[10000+8];
bool is[10000+8];

void E()
{
    tot = 0;
    memset(is, 1, sizeof(is));
    is[0] = is[1] = 0;
    for(int i = 2; i<10000+8; i++)
    {
        if(is[i])
        {
            pri[tot++] = i;
            for(int j = i+i; j<10000+8; j += i)
                is[j] = 0;
        }
    }
}

int main()
{
    E();
    while(~scanf("%d%d", &a, &b))
    {
        for(int i = a; i <= b; i++)
        {
            int id = 0, buffer = i;
            for(int j = 0; j < tot && pri[j]*pri[j] <= i; j++)
            {
                if(buffer%pri[j] == 0)
                {
                    while(buffer%pri[j] == 0)
                    {
                        en[id++] = pri[j];
                        buffer /= pri[j];
                    }
                }
            }
            if(buffer>1)en[id++] = buffer;
            printf("%d=", i);
            bool flag = 0;
            for(int j = 0; j<id; j++)
            {
                if(flag)printf("*");
                flag = 1;
                printf("%d", en[j]);
            }
            printf("\n");
        }
    }
    return 0;
}