Add Subtract Coding Problem
Problem
Write a function addSubtract to meet the requirement that, it will alternately adds and subtracts carried parameters.
For example:
add_subtract(7) -> 7
add_subtract(1)(2)(3) -> 1 + 2 - 3 -> 0
add_subtract(-5)(10)(3)(9) -> -5 + 10 - 3 + 9 -> 11
Solution
The idea is to have a addSubtract struct to keep tracking the last add/subtract result and the count of function calls. If the count is even number, then use subtract operation, otherwise, use add operation.
The following is a sample go code. You may also try it in go playground.
package main
import (
"fmt"
)
type addSubtract struct {
value int
callCounts int
}
func (a addSubtract) Reset() {
a.callCounts = 0
}
func (a addSubtract) Value() int {
return a.value
}
func (a addSubtract) AddSubtract(n int) addSubtract {
if a.callCounts == 0 {
return addSubtract{
value: n,
callCounts: a.callCounts + 1,
}
}
if a.callCounts%2 == 0 {
return addSubtract{
value: a.value - n,
callCounts: a.callCounts + 1,
}
}
return addSubtract{
value: a.value + n,
callCounts: a.callCounts + 1,
}
}
func main() {
as := addSubtract{}
fmt.Println(as.AddSubtract(7).Value())
as.Reset()
fmt.Println(as.AddSubtract(1).AddSubtract(2).AddSubtract(3).Value())
as.Reset()
fmt.Println(as.AddSubtract(-5).AddSubtract(10).AddSubtract(3).AddSubtract(9).Value())
}