数据结构作业——order（二叉树遍历）

#include<iostream>  
#include<cstdio>  
#include<cstring>  
using namespace std;  
const int maxn = 10005;  
int lson[maxn],rson[maxn],pos[maxn];  
bool first = true;  
  
void PreOrder(int x)  
{  
    if (x != 1) printf(" ");  
    printf("%d",x);  
    if (lson[x])    PreOrder(lson[x]);  
    if (rson[x])    PreOrder(rson[x]);  
}  
  
void PostOrder(int x)  
{  
    if (lson[x])    PostOrder(lson[x]);  
    if (rson[x])    PostOrder(rson[x]);  
    first?printf("%d",x):printf(" %d",x);  
    first = false;  
}  
  
int main()  
{  
    //freopen("input.txt","r",stdin);  
    //freopen("output.txt","w",stdout);  
    int N,i,tmp;  
    memset(lson,0,sizeof(lson));  
    memset(rson,0,sizeof(rson));  
    memset(pos,0,sizeof(pos));  
    scanf("%d",&N);  
    for (i = 1;i <= N;i++)  
    {  
        scanf("%d",&tmp);  
        if (tmp == 0)   continue;  
        if (!lson[tmp]) lson[tmp] = i;  
        else    rson[tmp] = i;    
    }  
    for (i = 1;i <= N;i++)  
    {  
        scanf("%d",&tmp);  
        pos[tmp] = i;  
    }  
    for (i = 1;i <= N;i++)  
    {  
        if (lson[i] && rson[i])  
        {  
            if (pos[rson[i]] < pos[lson[i]])  
            {  
                swap(rson[i],lson[i]);  
            }  
        }  
        else if (!lson[i] && rson[i])  
        {  
            if (pos[rson[i]] < pos[i])  
            {  
                lson[i] = rson[i];  
                rson[i] = 0;  
            }  
        }  
        else if (lson[i] && !rson[i])  
        {  
            if (pos[lson[i]] > pos[i])  
            {  
                rson[i] = lson[i];  
                lson[i] = 0;  
            }  
        }  
    }  
    PreOrder(1);printf("\n");  
    PostOrder(1);printf("\n");  
    return 0;  
}