### Sum of multiples of 3 or 5

Code
Diff
• ``````package kata

func IntegerSum(n int) (sum int) {
sum = n * (n+1) / 2
return
}

func AddMultiples(n int) (sum int) {
sum = IntegerSum((n-1)/3) * 3 + IntegerSum((n-1)/5) * 5 - IntegerSum((n-1)/15) * 15
return
}``````
• package kata
• func AddMultiples(n int) (sum int) {
• for i := 1; i < n; i++ {
• if i % 3 == 0 || i % 5 == 0 {
• sum += i
• }
• }
• func IntegerSum(n int) (sum int) {
• sum = n * (n+1) / 2
• return
• }
• func AddMultiples(n int) (sum int) {
• sum = IntegerSum((n-1)/3) * 3 + IntegerSum((n-1)/5) * 5 - IntegerSum((n-1)/15) * 15
• return
• }

### Numbers Divided by 2

Code
Diff
• ``````unsigned long long div2(unsigned long long a){

return a >> 1;
}``````
• unsigned long long div2(unsigned long long a){
• return a * 5 / 10;
• return a >> 1;
• }

### Leap Year

Code
Diff
• ``````bool isLeap(long n) {
return (n % 4 == 0 && n % 100 != 0) || (n % 400 == 0);
}``````
• bool isLeap(long n) {
• if ((n % 4 == 0 && n % 100 != 0) || (n % 400 == 0))
• return true;
• return false;
• return (n % 4 == 0 && n % 100 != 0) || (n % 400 == 0);
• }