6-20 No Less Than X in BST（20 point(s)）

6-20 No Less Than X in BST（20 point(s)）

You are supposed to output, in decreasing order, all the elements no less thanX in a binary search tree T.

Format of function:

void Print_NLT( Tree T,  int X );

where Tree is defined as the following:

typedef struct TreeNode *Tree;
struct TreeNode {
    int Element;
    Tree  Left;
    Tree  Right;
};

The function is supposed to use Output(X) to print X.

Sample program of judge:

#include <stdio.h>
#include <stdlib.h>

typedef struct TreeNode *Tree;
struct TreeNode {
    int Element;
    Tree  Left;
    Tree  Right;
};

Tree BuildTree(); /* details omitted */
void Output( int X ); /* details omitted */

void Print_NLT( Tree T,  int X );

int main()
{
    Tree T;
    int X;

    T = BuildTree();
    scanf("%d", &X);
    Print_NLT( T, X );
    printf("End\n");

    return 0;
}

/* Your function will be put here */

Sample Output 1 (for the tree shown in Figure 1):

92 91 90 85 81 80 End

Figure 1

Sample Output 2 (for the tree shown in Figure 2):

End

Figure 2

code:

void Print_NLT( Tree T,  int X ){
    if(T == NULL)return;//如果树为空，返回null
    //直接进行树的遍历，因为是从大到小输出不小于X的数
    //所以先遍历右子树，大于X的直接输出，再遍历左子树.
    Print_NLT(T->Right,X);
    if(T->Element>=X){
        printf("%d ",T->Element);
    }
    Print_NLT(T->Left,X);
    
}