本文主要向大家介绍了C/C++知识点之Self Numbers C语言 UVA640，通过具体的内容向大家展示，希望对大家学习C/C++知识点有所帮助。

In 1949 the Indian mathematician D.R. Kaprekar discovered a class of

numbers called self-numbers. For any positive integer n, define d(n) to

be n plus the sum of the digits of n. (The d stands for digitadition, a

term coined by Kaprekar.) For example, d(75) = 75 + 7 + 5 = 87. Given

any positive integer n as a starting point, you can construct the

infinite increasing sequence of integers n, d(n), d(d(n)), d(d(d(n))),

.... For example, if you start with 33, the next number is 33 + 3 + 3 =

39, the next is 39 + 3 + 9 = 51, the next is 51 + 5 + 1 = 57, and so you

generate the sequence

33, 39, 51, 57, 69, 84, 96, 111, 114, 120, 123, 129, 141, ...

The number n is called a generator of d(n). In the sequence above, 33

is a generator of 39, 39 is a generator of 51, 51 is a generator of 57,

and so on. Some numbers have more than one generator: for example, 101

has two generators, 91 and 100. A number with no generators is a

self-number. There are thirteen self-numbers less than 100: 1, 3, 5, 7,

9, 20, 31, 42, 53, 64, 75, 86, and 97.

Write a program to output all positive self-numbers less than or equal 1000000 in increasing order, one per line.

Sample Output

1

3

5

7

9

20

31

42

53

64

|

|

|

9903

9914

9925

9927

9938

9949

9960

9971

9982

9993

用离线计算的方法，计算出1000000以内的所有非自我数，将这些数筛掉后再从小到大按序输出。

1 //UVA 640

2 #include

3

4 int a[1000001];

5

6 int main(void){

7     int i,b,c;

8     for(i=0;i<=1000000;++i){

9         b=i;c=i;

10         while(c){

11             b+=c%10;

12             c/=10;

13         }

14         a[b]=1;

15     }

16     for(i=1;i<=1000000;++i)

17         if (!a[i]) printf("%d\n",i);

18     return 0;

19 }

View Code

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