规范格式

leetcode/0457.Circular-Array-Loop/457. Circular Array Loop.go

@@ -0,0 +1,37 @@
+package leetcode
+
+func circularArrayLoop(nums []int) bool {
+	if len(nums) == 0 {
+		return false
+	}
+	for i := 0; i < len(nums); i++ {
+		if nums[i] == 0 {
+			continue
+		}
+		// slow/fast pointer
+		slow, fast, val := i, getNextIndex(nums, i), 0
+		for nums[fast]*nums[i] > 0 && nums[getNextIndex(nums, fast)]*nums[i] > 0 {
+			if slow == fast {
+				// check for loop with only one element
+				if slow == getNextIndex(nums, slow) {
+					break
+				}
+				return true
+			}
+			slow = getNextIndex(nums, slow)
+			fast = getNextIndex(nums, getNextIndex(nums, fast))
+		}
+		// loop not found, set all element along the way to 0
+		slow, val = i, nums[i]
+		for nums[slow]*val > 0 {
+			next := getNextIndex(nums, slow)
+			nums[slow] = 0
+			slow = next
+		}
+	}
+	return false
+}
+
+func getNextIndex(nums []int, index int) int {
+	return ((nums[index]+index)%len(nums) + len(nums)) % len(nums)
+}