leadcode of Hot100 series - create a binary tree and traverse

Many topics related to the binary tree, so the first to write about some of the basic creation and traversal of a binary tree, native code debugging after convenience.
For convenience, as used herein char data type value used to initialize a data array.
Because these things relatively simple, here is not to do too much detail.

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create

1, the definition of some of the content:

// 二叉树节点结构体
typedef struct tree_node
{
    struct tree_node *pL;
    struct tree_node *pR;
    char data;
}TREE_NODE_S

// 输入数据的无效值，若读到无效值，则说明该节点为空
#define INVALID -1

// 全局变量，记录当前输入的数组位置
char count = 0

// 在遍历树的时候，需要对data做的操作
typedef void (*pfprocData)(char *p);

2, create the original binary tree using a recursive manner.
The basic idea with the preorder essentially the same, except that one is made to the data output, one is made to the data input.

TREE_NODE_S* createNode(char *str)
{
    TREE_NODE_S *pTemp = NULL;
    char data = *(str+count);
    count ++;
    if (data != INVALID)
    {
        pTemp = (TREE_NODE_S *)calloc(1, sizeof(TREE_NODE_S));
        if (NULL == pTemp)
        {
            return pTemp;
        }
        pTemp->data = data;  
        pTemp->pL = createNode(str);
        pTemp->pR = createNode(str);
    }
    return pTemp;
}

3, there is further provided a non-return value, the method of creating the transmission tree two pointers:

createNode2(TREE_NODE_S **p, char *str)
{
    TREE_NODE_S *pTemp = NULL;
    char data = *(str+count);
    count ++;
    if (data != INVALID)
    {
        pTemp = (TREE_NODE_S *)calloc(1, sizeof(TREE_NODE_S));
        if (NULL == pTemp)
        {
            *p = NULL;
            return;
        }
        // 这里直接对指针进行赋值
        *p = pTemp;
        pTemp->data = data;  
        createNode2(&(pTemp->pL), str);
        createNode2(&(pTemp->pR), str);
    }
    else
    {
        *p = NULL;
    }
    return;
}

Traversal

Three common preamble, in sequence, after traversal:

// 这里pfprocData，是用来处理结构体里面的数据部分的函数
void frontOrder(TREE_NODE_S *p, pfprocData pfunc)
{
    if (NULL == p)
    {
        return;
    }
    pfunc(&(p->data));
    frontOrder(p->pL, pfunc);
    frontOrder(p->pR, pfunc);
    return;
}

void middleOrder(TREE_NODE_S *p, pfprocData pfunc)
{
    if (NULL == p)
    {
        return;
    }
    middleOrder(p->pL, pfunc);
    pfunc(&(p->data));
    middleOrder(p->pR, pfunc);
    return;
}

void lastOrder(TREE_NODE_S *p, pfprocData pfunc)
{
    if (NULL == p)
    {
        return;
    }
    lastOrder(p->pL, pfunc);
    lastOrder(p->pR, pfunc);
    pfunc(&(p->data));
    return;
}

test

// 先创建出如下两种树，然后做遍历输出

//          1
//        /   \
//      2      4
//       \
//        3
char ps1[] = {1, 2, INVALID, 3, INVALID, INVALID, 4, INVALID, INVALID};

//        1
//      /   \
//    2      6
//   / \      \
//  3   5      7
//   \
//    4
char ps2[] = {1, 2, 3, INVALID, 4, INVALID, INVALID, 5, INVALID, INVALID, 6, INVALID, 7, INVALID, INVALID};

// 这里只对节点数据进行打印
void procData(char *p)
{
    printf("%u ", *p);
}

int main(void)
{
    TREE_NODE_S *pstTreeHead1 = NULL;
    TREE_NODE_S *pstTreeHead2 = NULL;

    pstTreeHead1 = createTree2(ps1);
    pstTreeHead2 = createTree2(ps2)

    // 如果使用第二个创建方法，则：
    // createTree(&pstTreeHead1, ps1);
    // createTree(&pstTreeHead2, ps2);

    printf("%-14s", "frontOrder:");
    frontOrder(pstTreeHead1, procData);
    printf("\n");

    printf("%-14s", "frontOrder:");
    frontOrder(pstTreeHead2, procData);
    printf("\n");

    printf("%-14s", "middleOrder:");
    middleOrder(pstTreeHead2, procData);
    printf("\n");

    printf("%-14s", "lastOrder:");
    lastOrder(pstTreeHead2, procData);
    printf("\n");
}