add new solutions

solutions/6/q605/solution.go

@@ -0,0 +1,22 @@
+package q605
+
+func canPlaceFlowers(flowerbed []int, n int) bool {
+	for i := 0; i < len(flowerbed); i++ {
+		if flowerbed[i] == 1 {
+			i++
+			continue
+		}
+
+		if (i == 0 || flowerbed[i-1] == 0) && (i == len(flowerbed)-1 || flowerbed[i+1] == 0) {
+			flowerbed[i] = 1
+			i++
+			n--
+			if n <= 0 {
+				return true
+			}
+		}
+	}
+	return n == 0
+}
+
+var _ = canPlaceFlowers

solutions/6/q643/solution.go

@@ -0,0 +1,23 @@
+package q643
+
+import "math"
+
+func findMaxAverage(nums []int, k int) float64 {
+	var maxSum = math.MinInt
+
+	sum := 0
+	for i := range nums {
+		if i < k-1 {
+			sum += nums[i]
+		} else {
+			sum += nums[i]
+			if i >= k {
+				sum -= nums[i-k]
+			}
+			maxSum = max(maxSum, sum)
+		}
+	}
+	return float64(maxSum) / float64(k)
+}
+
+var _ = findMaxAverage

solutions/6/q645/solution.go

@@ -0,0 +1,22 @@
+package q645
+
+func findErrorNums(nums []int) []int {
+	var duplicated, missing int
+	seen := make([]bool, len(nums))
+
+	for _, n := range nums {
+		if seen[n-1] {
+			duplicated = n
+		}
+		seen[n-1] = true
+	}
+	for i, ok := range seen {
+		if !ok {
+			missing = i + 1
+			break
+		}
+	}
+	return []int{duplicated, missing}
+}
+
+var _ = findErrorNums