规范格式

leetcode/0628.Maximum-Product-of-Three-Numbers/628. Maximum Product of Three Numbers.go

@@ -0,0 +1,59 @@
+package leetcode
+
+import (
+	"sort"
+)
+
+// 解法一 排序，时间复杂度 O(n log n)
+func maximumProduct(nums []int) int {
+	if len(nums) == 0 {
+		return 0
+	}
+	res := 1
+	if len(nums) <= 3 {
+		for i := 0; i < len(nums); i++ {
+			res = res * nums[i]
+		}
+		return res
+	}
+	sort.Ints(nums)
+	if nums[len(nums)-1] <= 0 {
+		return 0
+	}
+	return max(nums[0]*nums[1]*nums[len(nums)-1], nums[len(nums)-1]*nums[len(nums)-2]*nums[len(nums)-3])
+}
+
+func max(a int, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+// 解法二 模拟，时间复杂度 O(n)
+func maximumProduct1(nums []int) int {
+	n1, n2, n3 := -1<<63, -1<<63, -1<<63
+	n4, n5 := 0, 0
+	for _, v := range nums {
+		if v > n1 {
+			n3 = n2
+			n2 = n1
+			n1 = v
+		} else if v > n2 {
+			n3 = n2
+			n2 = v
+		} else if v > n3 {
+			n3 = v
+		}
+		if v < n4 {
+			n5 = n4
+			n4 = v
+		} else if v < n5 {
+			n5 = v
+		}
+	}
+	if n2*n3 > n4*n5 {
+		return n1 * n2 * n3
+	}
+	return n1 * n4 * n5
+}