Algorithms
Logic
Algebra
Mathematics
Arithmetic progression, int itself an integer number of divisions by 3, 7, 21;
int foo(int n){ return ((int)n/3 *(3 + n - n % 3)+ (int)n/7 *(7 + n- n % 7) - (int)n/21 *(21 + n - n % 21))/2; }
- int foo(int n){
if (n < 0) {return 0;}int count_3 = n / 3;int count_7 = n / 7;int count_21 = n / 21;- return
count_3 *(3 + n - n % 3) /2 +count_7 *(7 + n- n % 7) / 2 -count_21 *(21 + n - n % 21) /2;- ((int)n/3 *(3 + n - n % 3)+
- (int)n/7 *(7 + n- n % 7) -
- (int)n/21 *(21 + n - n % 21))/2;
- }