Add solution 0382

leetcode/0382.Linked-List-Random-Node/382. Linked List Random Node.go

@@ -0,0 +1,46 @@
+package leetcode
+
+import (
+	"math/rand"
+
+	"github.com/halfrost/LeetCode-Go/structures"
+)
+
+// ListNode define
+type ListNode = structures.ListNode
+
+/**
+ * Definition for singly-linked list.
+ * type ListNode struct {
+ *     Val int
+ *     Next *ListNode
+ * }
+ */
+type Solution struct {
+	head *ListNode
+}
+
+/** @param head The linked list's head.
+  Note that the head is guaranteed to be not null, so it contains at least one node. */
+func Constructor(head *ListNode) Solution {
+	return Solution{head: head}
+}
+
+/** Returns a random node's value. */
+func (this *Solution) GetRandom() int {
+	scope, selectPoint, curr := 1, 0, this.head
+	for curr != nil {
+		if rand.Float64() < 1.0/float64(scope) {
+			selectPoint = curr.Val
+		}
+		scope += 1
+		curr = curr.Next
+	}
+	return selectPoint
+}
+
+/**
+ * Your Solution object will be instantiated and called as such:
+ * obj := Constructor(head);
+ * param_1 := obj.GetRandom();
+ */