// Data Segment
union Data {
    struct Tree { /* ... 赤黒木の定義と同様 */ } tree;
    struct Node { /* ... 赤黒木の定義と同様 */ } node;

    /* for verification */
    struct IterElem {
        unsigned int val;
        struct IterElem* next;
    } iterElem;
    struct Iterator {
        struct Tree* tree;
        struct Iterator* previousDepth;
        struct IterElem* head;
        struct IterElem* last;
        unsigned int  iteratedValue;
        unsigned long iteratedPointDataNum;
        void*         iteratedPointHeap;
    } iterator;
    struct AkashaInfo {
        unsigned int minHeight;
        unsigned int maxHeight;
        struct AkashaNode* akashaNode;
    } akashaInfo;
    struct AkashaNode {
        unsigned int       height;
        struct Node*       node;
        struct AkashaNode* nextAkashaNode;
    } akashaNode;
};