Write a routine to list out the nodes of a binary tree in "level-order". List the root, then nodes at depth 1, followed by nodes at depth 2, and so on. You must do this in linear time.

Format of functions:

void Level_order ( Tree T, void (*visit)(Tree ThisNode) );

where void (*visit)(Tree ThisNode) is a function that handles ThisNode being visited by Level_order, and Tree is defined as the following:

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

Sample program of judge:

#include <stdio.h>
#include <stdlib.h> #define MaxTree 10 /* maximum number of nodes in a tree */
typedef int ElementType; typedef struct TreeNode *Tree;
struct TreeNode {
ElementType Element;
Tree Left;
Tree Right;
}; Tree BuildTree(); /* details omitted */
void PrintNode( Tree NodePtr )
{
printf(" %d", NodePtr->Element);
} void Level_order ( Tree T, void (*visit)(Tree ThisNode) ); int main()
{
Tree T = BuildTree();
printf("Level-order:");
Level_order(T, PrintNode);
return 0;
} /* Your function will be put here */

Sample Output (for the tree shown in the figure):

6-11 Level-order Traversal(25 分)-LMLPHP

Level-order: 3 5 6 1 8 10 9
代码:
void Level_order ( Tree T, void (*visit)(Tree ThisNode) )
{
Tree s[];
int head = ,tail = ;
if(T)s[tail ++] = T;
while(head < tail)
{
if(s[head] -> Left)s[tail ++] = s[head] -> Left;
if(s[head] -> Right)s[tail ++] = s[head] -> Right;
(*visit)(s[head ++]);
}
}
05-11 22:13
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