Re-translate the Japanese version (#1871)

* Retranslate Japanese docs with GPT-5.4

* Retranslate Japanese code with GPT-5.4

ja/codes/c/utils/vertex.h

@@ -0,0 +1,49 @@
+/**
+ * File: vertex.h
+ * Created Time: 2023-10-28
+ * Author: krahets (krahets@163.com)
+ */
+
+#ifndef VERTEX_H
+#define VERTEX_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* 頂点構造体 */
+typedef struct {
+    int val;
+} Vertex;
+
+/* コンストラクタ。新しいノードを初期化する */
+Vertex *newVertex(int val) {
+    Vertex *vet;
+    vet = (Vertex *)malloc(sizeof(Vertex));
+    vet->val = val;
+    return vet;
+}
+
+/* 値の配列を頂点配列に変換 */
+Vertex **valsToVets(int *vals, int size) {
+    Vertex **vertices = (Vertex **)malloc(size * sizeof(Vertex *));
+    for (int i = 0; i < size; ++i) {
+        vertices[i] = newVertex(vals[i]);
+    }
+    return vertices;
+}
+
+/* 頂点配列を値配列に変換 */
+int *vetsToVals(Vertex **vertices, int size) {
+    int *vals = (int *)malloc(size * sizeof(int));
+    for (int i = 0; i < size; ++i) {
+        vals[i] = vertices[i]->val;
+    }
+    return vals;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // VERTEX_H