Leetcode Note: Go - Baseball Game

func calPoints(ops []string) int {
    stack := make([]int, len(ops))
    top := 0

    for i := 0; i < len(ops); i++ {
        op := ops[i]
        switch op {
        case "+":
            last1 := stack[top-1]
            last2 := stack[top-2]
            stack[top] = last1 + last2
            top += 1
        case "D":
            last1 := stack[top-1]
            stack[top] = last1 * 2
            top += 1
        case "C":
            top -= 1
        default:
            stack[top], _ = strconv.Atoi(op)
            top += 1
        }
    }

    points := 0
    for i := 0; i < top; i++ {
        points += stack[i]
    }
    return points
}