03-树3 Tree Traversals Again

根据题目:
入栈的顺序即为先序遍历的顺序
出栈的顺序即为中序遍历的顺序
然后根据先序遍历、中序遍历来构建二叉树

AC代码

#include
#include
#include
#include
#include

using namespace std;

typedef struct TreeNode *BinTree;
struct TreeNode{
    int data;
    BinTree Left;
    BinTree Right;
};

int flag = 1;

BinTree CreateBinTree(int *Pre,int *In,int Len)
{
    BinTree T;
    int i;

    if(!Len)
        return NULL;

    T = (BinTree)malloc(sizeof(struct TreeNode));
    T->data = Pre[0];
    for(i=0;iif(Pre[0] == In[i])
            break;

    T->Left = CreateBinTree(Pre+1,In,i);
    T->Right = CreateBinTree(Pre+i+1,In+i+1,Len-i-1);

    return T;
}

void PostOrderPrint(BinTree BT)
{
    if(BT){
        PostOrderPrint(BT->Left);
        PostOrderPrint(BT->Right);
        if(flag){
            flag = 0;
            printf("%d",BT->data);
        }
        else
            printf(" %d",BT->data);
    }
}

int main()
{
    int PreOrder[30]={0};
    int InOrder[30]={0};
    int PostOrder[30]={0};
    int N,data;
    int PreIndex = 0,InIndex = 0,PostIndex = 0;
    stack<int> inputstack;
    scanf("%d",&N);
    string str;
    for(int i=0;i<2*N;i++)
    {
        cin>>str;
        if(str == "Push"){
            scanf("%d",&data);
            PreOrder[PreIndex++] = data;
            inputstack.push(data);
        }
        else if(str == "Pop"){
            InOrder[InIndex++] = inputstack.top();
            inputstack.pop();
        }
    }
//  for(int i=0;i
//      printf("%d ",PreOrder[i]);
//  printf("\n");
//  for(int i=0;i
//      printf("%d ",InOrder[i]);
    BinTree T = NULL;
    T = CreateBinTree(PreOrder,InOrder,N);
    PostOrderPrint(T);
    printf("\n");

    return 0;
}