PAT 1043. Is It a Binary Search Tree

题目:http://pat.zju.edu.cn/contests/pat-a-practise/1043

题解:

1:通过输入构造二叉排序树

2:先序遍历并与输入顺序比较

3:如果比较不符合再构造镜像二叉排序树

4:比较输出结果

代码:

#include
#include
#include
#include
#include
#include
#include
#include
#include
using namespace std;
#define INF 0x6fffffff
#define MAX 1005
struct point
{
    int value;
    int left;
    int right;
} node[MAX];
int a[MAX],b[MAX];
int deep;
void dfs(int x,int idx)
{//构造二叉树
    if(node[x].value>node[idx].value)
    {
        //应在当前结点左子树
        if(node[x].left==-1)
            node[x].left=idx;
        else
            dfs(node[x].left,idx);
    }
    else
    {
        //应在当前结点右子树
        if(node[x].right==-1)
            node[x].right=idx;
        else
            dfs(node[x].right,idx);
    }
}
void dfsP(int x,int idx)
{//构造镜像排序二叉树
    if(node[x].value>node[idx].value)
    {
        //应在当前结点右子树
        if(node[x].right==-1)
            node[x].right=idx;
        else
            dfsP(node[x].right,idx);
    }
    else
    {
        //应在当前结点左子树
        if(node[x].left==-1)
            node[x].left=idx;
        else
            dfsP(node[x].left,idx);
    }
}
void dfsPre(int x)
{//先序遍历
    b[deep]=node[x].value;
    ++deep;
    if(node[x].left!=-1)
        dfsPre(node[x].left);
    if(node[x].right!=-1)
        dfsPre(node[x].right);
}
void dfsPost(int x)
{//后序遍历
    if(node[x].left!=-1)
        dfsPost(node[x].left);
    if(node[x].right!=-1)
        dfsPost(node[x].right);
    b[deep]=node[x].value;
    ++deep;
}
int main()
{
    int n;
    scanf("%d",&n);
    for(int i=0; i

来源: http://blog.csdn.net/acm_ted/article/details/20715415


你可能感兴趣的:(PAT)