前序，中序，后序，层序互求

1、中序，后序重构二叉树 

struct node *rebuild(char *a, char *b, int n)//a为已知中序，b为已知后序
{
    struct node *root;
    int i;
    if(n==0) return NULL;
    root = (struct node*)malloc(sizeof(struct node));
    root->data = b[n-1];
    for(i = 0; i<n; i++)
    {
        if(a[i] == b[n-1]) break;
    }
    root->lchild = rebuild(a ,b, i);
    root->rchild = rebuild(a+i+1, b+i, n-i-1);
    return root;
}

 2、前序，中序重构二叉树

struct node *rebuild(char *a, char *b, int n)//a为已知前序， b为已知中序
{
    struct node *root;
    int i;
    if(n==0) return NULL;
    root = (struct node*)malloc(sizeof(struct node));
    root->data = a[0];
    for(i = 0; i<n; i++)
    {
        if(b[i] == a[0]) break;
    }
    root->lchild = rebuild(a+1,b, i);
    root->rchild = rebuild(a+i+1, b+i+1, n-i-1);
    return root;
}

待更新