add new solutions

solutions/1/q150/solution.go

@@ -1,24 +1,29 @@
 package q150
 
-func twoSum(numbers []int, target int) []int {
-	l, r := 0, len(numbers)-1
+import "strconv"
 
-	for l < r {
-		for numbers[r]+numbers[l] > target {
-			r--
-		}
-		if numbers[r]+numbers[l] == target {
-			return []int{l + 1, r + 1}
-		}
+func evalRPN(tokens []string) int {
+	stack := make([]int, 0, len(tokens)/2)
+	for _, s := range tokens {
+		height := len(stack)
 
-		for numbers[r]+numbers[l] < target {
-			l++
-		}
-		if numbers[r]+numbers[l] == target {
-			return []int{l + 1, r + 1}
+		switch s {
+		case "+":
+			stack[height-2] += stack[height-1]
+		case "-":
+			stack[height-2] -= stack[height-1]
+		case "*":
+			stack[height-2] *= stack[height-1]
+		case "/":
+			stack[height-2] /= stack[height-1]
+		default:
+			num, _ := strconv.ParseInt(s, 10, strconv.IntSize)
+			stack = append(stack, int(num))
+			continue
 		}
+		stack = stack[:height-1]
 	}
-	return []int{} // impossible
+	return stack[0]
 }
 
-var _ = twoSum
+var _ = evalRPN

solutions/1/q167/solution.go

@@ -0,0 +1,24 @@
+package q167
+
+func twoSum(numbers []int, target int) []int {
+	l, r := 0, len(numbers)-1
+
+	for l < r {
+		for numbers[r]+numbers[l] > target {
+			r--
+		}
+		if numbers[r]+numbers[l] == target {
+			return []int{l + 1, r + 1}
+		}
+
+		for numbers[r]+numbers[l] < target {
+			l++
+		}
+		if numbers[r]+numbers[l] == target {
+			return []int{l + 1, r + 1}
+		}
+	}
+	return []int{} // impossible
+}
+
+var _ = twoSum