#define ElemType int

typedef struct BiTNode {
    ElemType data;
    struct BiTNode *lchild, *rchild;
    int count;
} BiTNode, *BiTree;

#include <stdlib.h>

BiTree Search(BiTree t, int k) {
    static int count = 0;
    static BiTree p;
    if (t) {
        Search(t->lchild, k);
        count++;
        if (count == k) p = t;
        else Search(t->rchild, k);
    }
    return p;
}

BiTree SearchK(BiTree t, int k) {
    static int count = 0;
    static BiTree p;
    if (t) {
        if (t->lchild) {
            if (t->lchild->count < k) {
                count += t->lchild->count + 1;
                if (count == k) p = t;
                else SearchK(t->rchild, k - count);
            } else SearchK(t->lchild, k);
        }

        count++;
        if (count == k) p = t;

        if (t->rchild) {
            if (t->rchild->count < k) {
                count += t->lchild->count + 1;
                if (count == k) p = t;
                else SearchK(t->lchild, k - count);
            } else {
                count++;
                if (count == k) p = t;
                SearchK(t->rchild, k - count);
            }
        }
    }
    return p;
}