【已知中序后序二叉树求前序二叉树】

int InOrder[1000], PosterOrder[1000];
typedef struct BiTNode {
    int data;
    struct BiTNode *LChild, *RChild;
} BiTNode, *BiTree;
int find(int *InOrder, int &x, int n) {
    for(int i = 0; i< n; ++i) {if(InOrder[i] == x) return i;}
    return -1;
}
void PreOrderTraverse(BiTree T, int n) {
    if(T == NULL) return ;
    printf("%d ", T -> data);
    PreOrderTraverse(T -> LChild, n);
    PreOrderTraverse(T -> RChild, n);
}
BiTNode *CreateInTree(int *PosterOrder, int *InOrder, int n) {
    BiTNode *in;
    if(PosterOrder == NULL || InOrder == NULL || n ==0) return NULL;
    else {
        in = (BiTNode *)malloc(sizeof(BiTNode));
        in -> data = PosterOrder[n - 1];
        int i = find(InOrder, PosterOrder[n - 1], n);
        if(i != -1) {
            in -> LChild = CreateInTree(PosterOrder, InOrder, i);
            in -> RChild = CreateInTree(PosterOrder + i, InOrder + i + 1, n - i - 1);
            return in;
        }
        return NULL;
    }
}
void destoryBiTree(BiTree &T) {
    if(T == NULL) return ;
    destoryBiTree(T -> LChild);
    destoryBiTree(T -> RChild);
    free(T);
    T = NULL;
}
int main(int argc, char *argv[])
{
    BiTree T;
    int n, i;
    while(scanf("%d", &n) != EOF) {
        for(i = 0; i < n; i++) scanf("%d", &PosterOrder[i]);
        for(i = 0; i < n; i++) scanf("%d", &InOrder[i]);
        T = CreateInTree(PosterOrder, InOrder, n);
        PreOrderTraverse(T, n);
        destoryBiTree(T);
        puts("");
    }
    return 0;
}
7
3 1 2 5 6 7 4
3 2 1 4 5 7 6

4 2 3 1 7 5 6