完美数

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#include <stdio.h> 
#include <stdlib.h> 

#define N 1000 
#define P 10000 

int prime(int*);  // 求质数表 
int factor(int*, int, int*);  // 求factor 
int fsum(int*, int);  // sum ot proper factor 

int main(void) { 
    int ptable[N+1] = {0}; // 储存质数表 
    int fact[N+1] = {0};   // 储存因式分解结果 
    int count1, count2, i; 

    count1 = prime(ptable); 

    for(i = 0; i <= P; i++) { 
        count2 = factor(ptable, i, fact); 
        if(i == fsum(fact, count2)) 
            printf("Perfect Number: %d\n", i); 
    } 
    
    printf("\n"); 

    return 0; 
} 

int prime(int* pNum) { 
    int i, j; 
    int prime[N+1]; 

    for(i = 2; i <= N; i++) 
        prime[i] = 1; 

    for(i = 2; i*i <= N; i++) { 
        if(prime[i] == 1) { 
            for(j = 2*i; j <= N; j++) { 
                if(j % i == 0) 
                    prime[j] = 0; 
            } 
        } 
    } 

    for(i = 2, j = 0; i < N; i++) { 
        if(prime[i] == 1) 
            pNum[j++] = i; 
    } 

    return j; 
} 

int factor(int* table, int num, int* frecord) { 
    int i, k; 

    for(i = 0, k = 0; table[i] * table[i] <= num;) { 
        if(num % table[i] == 0) { 
            frecord[k] = table[i]; 
            k++; 
            num /= table[i]; 
        } 
        else 
            i++; 
    } 

    frecord[k] = num; 

    return k+1; 
} 

int fsum(int* farr, int c) { 
    int i, r, s, q; 

    i = 0; 
    r = 1; 
    s = 1; 
    q = 1; 

    while(i < c) { 
        do { 
            r *= farr[i]; 
            q += r; 
            i++; 
        } while(i < c-1 && farr[i-1] == farr[i]); 
        s *= q; 
        r = 1; 
        q = 1; 
    } 

    return s / 2; 
}

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import java.util.ArrayList;

public class PerfectNumber {
    public static int[] lessThan(int number) {
        int[] primes = Prime.findPrimes(number);

        ArrayList list = new ArrayList();
        
        for(int i = 1; i <= number; i++) { 
            int[] factors = factor(primes, i); 
            if(i == fsum(factors)) 
                list.add(new Integer(i));
        } 

        int[] p = new int[list.size()];
        Object[] objs = list.toArray(); 
        for(int i = 0; i < p.length; i++) {
            p[i] = ((Integer) objs[i]).intValue();
        }
        
        return p;
    }
    
    private static int[] factor(int[] primes, int number) { 
        int[] frecord = new int[number];
        int k = 0;
        
        for(int i = 0; Math.pow(primes[i], 2) <= number;) { 
            if(number % primes[i] == 0) { 
                frecord[k] = primes[i]; 
                k++; 
                number /= primes[i]; 
            } 
            else 
                i++; 
        } 

        frecord[k] = number; 

        return frecord; 
    } 

    private static int fsum(int[] farr) { 
        int i, r, s, q; 

        i = 0; 
        r = 1; 
        s = 1; 
        q = 1; 

        while(i < farr.length) { 
            do { 
                r *= farr[i]; 
                q += r; 
                i++; 
            } while(i < farr.length - 1 &&
                    farr[i-1] == farr[i]); 
            s *= q; 
            r = 1; 
            q = 1; 
        } 

        return s / 2; 
    }
    
    public static void main(String[] args) {
        int[] pn = PerfectNumber.lessThan(1000);
     
        for(int i = 0; i < pn.length; i++) {
            System.out.print(pn[i] + " ");
        }
        
        System.out.println();
    }
}