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package main
import (
"fmt"
"strconv"
"github.com/emirpasic/gods/stacks/arraystack"
)
func evalRPN(tokens []string) int {
st := arraystack.New()
for _, op := range tokens {
switch op {
case "+":
{
val1, _ := st.Pop()
val2, _ := st.Pop()
res := val1.(int) + val2.(int)
fmt.Printf("%d + %d = %d\n", val1, val2, res)
st.Push(res)
}
case "-":
{
val1, _ := st.Pop()
val2, _ := st.Pop()
res := val2.(int) - val1.(int)
fmt.Printf("%d - %d = %d\n", val2, val1, res)
st.Push(res)
}
case "*":
{
val1, _ := st.Pop()
val2, _ := st.Pop()
res := val1.(int) * val2.(int)
fmt.Printf("%d * %d = %d\n", val1, val2, res)
st.Push(res)
}
case "/":
{
val1, _ := st.Pop()
val2, _ := st.Pop()
res := val2.(int) / val1.(int)
fmt.Printf("%d / %d = %d\n", val2, val1, res)
st.Push(res)
}
default:
{
val1, _ := strconv.Atoi(op)
st.Push(val1)
}
}
}
final, _ := st.Pop()
return final.(int)
}
func main() {
fmt.Println(evalRPN([]string{"2", "1", "+", "3", "*"}))
fmt.Println(evalRPN([]string{"4", "13", "5", "/", "+"}))
fmt.Println(evalRPN([]string{"10", "6", "9", "3", "+", "-11", "*", "/", "*", "17", "+", "5", "+"}))
}
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