Sum of the HDU 1406 final number factor

 

Definition of final number: if the sum of all the factors of a positive integer greater than 1 is equal to its own, it is called the final number. For example, 6 and 28 are all final numbers: 6 = 1 + 2 + 3; 28 = 1 + 2 + 4 + 7 + 14.
The task of this question is to determine the number of completion numbers between two positive integers.

 

Today, this question is the same idea as that of yesterday. We use a method similar to filtering prime numbers to calculate the sum of factors.

 

# Include

 
  
Const int MAXN = 10000 + 2; const int N = MAXN> 1; int sum [MAXN] = {0}; int main () {for (int I = 2; I

  
   
B) {int temp = a; a = B; B = temp;} int cnt = 0; for (int I = a; I <= B; I ++) {if (sum [I] = i-1) // because my array is 0 at the beginning, and the factor contains 1cnt ++;} printf (% d, cnt );} return 0 ;}