【已知前序中序二叉树求后序二叉树】

int PreOrder[1000], InOrder[1000];
int flag, n;
typedef struct BiTNode {
    int data;
    struct BiTNode *LChild, RChild;
} BiTNode, *BiTree;
void PostOrderTraverse(BiTree T) {
    if(T == NULL) return ;
    PostOrderTraverse(T -> LChild);
    PostOrderTraverse(T -> RChild);
    if(T -> data == PreOrder[0]) printf("%d\n", T -> data);
    else printf("%d ", T -> data);
}
BiTNode *CreatePreTree(int *PreOrder, int *InOrder, int n) {
    int i;
    BiTNode *pre;
    for(i = 0; i < n; ++i) {
        if(PreOrder[0] == InOrder[i]) {
            pre = (BiTNode *)malloc(sizeof(BiTNode));
            pre -> data = PreOrder[0];
            pre -> LChild = CreatePreTree(PreOrder + 1, InOrder, i);
            pre -> RChild = CreatePreTree(PreOrder + i + 1, InOrder + i + 1, n - i - 1);
            return pre;
        }
    }
    return NULL;
}
void destoryBiTree(BiTree &T) {
    if(T == NULL) return ;
    destoryBiTree(T -> LChild);
    destoryBiTree(T -> RChild);
    free(T);
}
int main() {
    int i;
    BiTree T;
    while(scanf("%d", &n) != EOF) {
        for (i = 0; i < n; ++i) scanf("%d", PreOrder + i);
        for (i = 0; i < n; ++i) scanf("%d", InOrder + i);
        flag = 0;
        T = CreatePreTree(PreOrder, InOrder, n);
        PostOrderTraverse(T);
        destoryBiTree(T);
    }
    return 0;
}
7
4 2 3 1 7 5 6
3 2 1 4 5 7 6

3 1 2 5 6 7 4