“水仙花数”的扩展问题

我从09分开始计时，11分结束，接近5分钟吧，好慢啊
#include<iostream>
#include<cmath>
#include <ctime>
//#include <stdio.h>
using namespace std;

int main()
{  int a[15]{}; int tem=0;int count=0;int i=0;
int begintime,endtime;
    begintime=clock();  //计时开始
   
for(int n=100;n<100000000;++n)
{ //int n=153;
int c=n;

do{ a[i]=c%10;
    c=c/10;
   ++ i;
   ++count;
    } while (c!=0);
   // cout<<count;
    for (int j=0;j<count;++j)
    {
    c+=pow(a[j],count);
        }
        //count=0;
if(c==n)
{printf("%d\n",c);}
count=0;i=0;
}
endtime = clock();  //计时结束
    printf("\n\nRunning Time：%dms\n", endtime-begintime);
    return 0;
}

#include <stdio.h>

void foo( unsigned n )
{
    static unsigned long long table[11][11] = { 0 };
    if( table[0][0] == 0 )
    {
        for( size_t i=0; i!=sizeof(table)/sizeof(*table); ++i )
        {
            unsigned long long t = 1;
            for( size_t j=0; j!=sizeof(*table)/sizeof(**table); ++j, t*=i )
                table[i][j] = t;
        }
    }

    for( unsigned a=0; a<=n; ++a )
    for( unsigned b=0; b<=n-a; ++b )
    for( unsigned c=0; c<=n-a-b; ++c )
    for( unsigned d=0; d<=n-a-b-c; ++d )
    for( unsigned e=0; e<=n-a-b-c-d; ++e )
    for( unsigned f=0; f<=n-a-b-c-d-e; ++f )
    for( unsigned g=0; g<=n-a-b-c-d-e-f; ++g )
    for( unsigned h=0; h<=n-a-b-c-d-e-f-g; ++h )
    for( unsigned i=0; i<=n-a-b-c-d-e-f-g-h; ++i )
    {
        unsigned long long sum = a*table[1][n] + b*table[2][n] + c*table[3][n] + d*table[4][n] + e*table[5][n] + f*table[6][n] + g*table[7][n] + h*table[8][n] + i*table[9][n];
        if( sum >= table[10][n-1] )
        {
            unsigned buf[10] = { 0, a, b, c, d, e, f, g, h, i };
            for( unsigned long long s=sum; s; s/=10 )
                --buf[s%10];
            if( buf[1]==0 && buf[2]==0 && buf[3]==0 && buf[4]==0 && buf[5]==0 && buf[6]==0 && buf[7]==0 && buf[8]==0 && buf[9]==0 )
                printf( "    %llu\n", sum );
        }
    }
}

int main( void )
{
    puts("3位水仙花有:"); foo(3);
    puts("4位水仙花有:"); foo(4);
    puts("5位水仙花有:"); foo(5);
    puts("6位水仙花有:"); foo(6);
    puts("7位水仙花有:"); foo(7);
    puts("8位水仙花有:"); foo(8);
    puts("9位水仙花有:"); foo(9);
    puts("10位水仙花有:"); foo(10);

    return 0;
}