add new solutions

solutions/33/q3354/solution.go

@@ -0,0 +1,28 @@
+package q3354
+
+func countValidSelections(nums []int) int {
+	sumR := 0
+	for i := range nums {
+		sumR += nums[i]
+	}
+
+	sumL := 0
+	nValid := 0
+	for i := range nums {
+		sumR -= nums[i]
+		if i > 0 {
+			sumL += nums[i-1]
+		}
+		if nums[i] == 0 {
+			diff := sumL - sumR
+			if diff == 0 {
+				nValid += 2
+			} else if diff*diff == 1 {
+				nValid++
+			}
+		}
+	}
+	return nValid
+}
+
+var _ = countValidSelections