二叉树A和B的每个节点的数据(int型数据)存储在不同文件中,存储方式为前序遍历和中序遍历,根据这两种遍历重建二叉树,并且判断二叉树A是否包含二叉树B。
1、算法描述
(1)首先将节点数据的前序遍历和中序遍历序列读入数组
(2)分别根据各自的前序遍历和中序遍历重建二叉树A和B
(3)判断B是否在A中
代码:
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <memory.h>
#include <stack>
using namespace std;
enum COMMON_SIZE
{
BUF_MAX_SIZE = 1024,
MAX_NUM_LEN = 10,
};
enum ERROR_VALUE
{
INPUT_PARAM_ERROR = -1,
OPEN_FILE_ERROR = -2,
FILE_NOT_EXSIT = -3,
FILE_IS_EMTPY = -4,
ALLOCA_FAILURE = -5,
REBUILD_BTREE_ERROR = -6,
NUM_OVERFLOW_ERROR = -7,
};
typedef struct BTreeNode_t_{
int m_nValue;
struct BTreeNode_t_ *m_pLeft;
struct BTreeNode_t_ *m_pRight;
} BTreeNode_t;
void release_btree( BTreeNode_t *pRoot){
if( pRoot == NULL )
return;
if( pRoot->m_pLeft )
release_btree( pRoot->m_pLeft);
if( pRoot->m_pRight)
release_btree( pRoot->m_pRight);
free(pRoot);
pRoot = NULL;
return;
}
BTreeNode_t * reconstruct_btree_by_preinorder( int *pPreOrder, int *pInOrder, int tree_nodes_total){
if( pPreOrder == NULL || pInOrder == NULL ){
fprintf(stderr, "ERROR: while construct btree by preinorder\n");
return NULL;
}
int m_nValue = pPreOrder[0];
int root_data_index = -1;
int i = 0;
for( i = 0; i < tree_nodes_total; ++i ){
if( pPreOrder[0] == pInOrder[i] ){
root_data_index = i;
break;
}
}
if( root_data_index == -1 ){
fprintf(stderr, "note: pPreOrder[0] is %d, pInOrder[0] is %d\n",
pPreOrder[0], pInOrder[0]);
fprintf(stderr, "note: root_data_index is -1, total nodes: %d\n", tree_nodes_total);
return NULL;
}
BTreeNode_t *pRoot = NULL;
pRoot = (BTreeNode_t *) malloc( sizeof( BTreeNode_t ));
if( pRoot == NULL ){
fprintf(stderr, "ERROR: can't alloca btree node: %d\n", m_nValue);
return NULL;
}
pRoot->m_nValue = m_nValue;
pRoot->m_pLeft = NULL;
pRoot->m_pRight = NULL;
int left_tree_len = root_data_index;
int right_tree_len = tree_nodes_total - left_tree_len - 1;
int *pleft_preorder = pPreOrder + 1;
int *pright_preorder = pPreOrder + 1 + left_tree_len;
int *pleft_inorder = pInOrder;
int *pright_inorder = pInOrder + left_tree_len + 1;
if( left_tree_len > 0 )
{
pRoot->m_pLeft = reconstruct_btree_by_preinorder( pleft_preorder, pleft_inorder, left_tree_len);
if( pRoot->m_pLeft == NULL ){
fprintf(stderr, "ERROR: failure to rebuild leftree, now release data: %d\n",
m_nValue);
release_btree( pRoot);
pRoot = NULL;
return NULL;
}
}
if( right_tree_len > 0 ){
pRoot->m_pRight = reconstruct_btree_by_preinorder( pright_preorder, pright_inorder, right_tree_len );
if( pRoot->m_pRight == NULL ){
fprintf(stderr, "ERROR: failure to right tree, now release data: %d\n",
m_nValue);
release_btree( pRoot );
pRoot = NULL;
return NULL;
}
}
return pRoot;
}
int get_traver_data( char *buf, int *pOrder, int *order_len ){
if( buf == NULL || pOrder == NULL ){
return INPUT_PARAM_ERROR;
}
char *ptr = buf;
char *pNumStart = ptr;
int i = 0;
int numLen = 0;
int get_no_num = 0;
int flag = 0;
fprintf(stderr, "note: now enter get_traver_data()\n");
while( *ptr != '\0' ){
if( ( *ptr >= '0' ) && ( *ptr <= '9') ){
++numLen;
} else if( *ptr == ' ' ){
*ptr = '\0';
if( numLen > 0 && numLen <= MAX_NUM_LEN ){
pOrder[i] = atoi( ptr - numLen );
fprintf(stderr, "note: num is: %d\n", pOrder[i]);
++i;
}
else if ( numLen > MAX_NUM_LEN){
flag = NUM_OVERFLOW_ERROR;
break;
}
numLen = 0;
} else{
get_no_num = -1;
break;
}
++ptr;
}
if( numLen != 0 ){
pOrder[i] = atoi( ptr - numLen);
fprintf(stderr, "note: num is: %d\n", pOrder[i]);
}
if( get_no_num != 0 )
return get_no_num;
*order_len = i + 1;
fprintf(stderr, "note: finish get_traver_data()\n");
return flag;
}