Add kotlin code for the utils file (#1175)

* feat(kotlin): add kotlin code for utils file.

* Update ListNode.kt

* Update PrintUtil.kt

---------

Co-authored-by: Yudong Jin <krahets@163.com>

codes/kotlin/utils/Vertex.kt

@@ -0,0 +1,30 @@
+/**
+ * File: Vertex.kt
+ * Created Time: 2024-01-25
+ * Author: curtishd (1023632660@qq.com)
+ */
+
+package utils
+
+/* 顶点类 */
+class Vertex(val value: Int) {
+    companion object {
+        /* 输入值列表 vals ，返回顶点列表 vets */
+        fun valsToVets(vals: IntArray): Array<Vertex?> {
+            val vets = arrayOfNulls<Vertex>(vals.size)
+            for (i in vals.indices) {
+                vets[i] = Vertex(vals[i])
+            }
+            return vets
+        }
+
+        /* 输入顶点列表 vets ，返回值列表 vals */
+        fun vetsToVals(vets: List<Vertex?>): List<Int> {
+            val vals = ArrayList<Int>()
+            for (vet in vets) {
+                vals.add(vet!!.value)
+            }
+            return vals
+        }
+    }
+}