文章目录
〇、前言
这两周开始跟着【MOOC-浙江大学-陈越、何钦铭-数据结构】进行数据结构与算法的学习，特此记录复习一下，虽然记不住，但是一直记一直记一直记，成为复读机就好了。
一、二叉搜索树
二、平衡二叉树
三、平衡二叉树的调整
四、是否同一棵二叉搜索树
实现在后面的第一题！
五、课后题
1、04-树4 是否同一棵二叉搜索树 (25分)
输入样例:
4 2
3 1 4 2
3 4 1 2
3 2 4 1
2 1
2 1
1 2
0
输出样例:
Yes
No
No
#include <stdio.h>
#include <stdlib.h>
typedef struct TreeNode *Tree;
struct TreeNode {
int v;
Tree Left, Right;
int flag;
};
Tree NewNode( int V )
{
Tree T = (Tree)malloc(sizeof(struct TreeNode));
T->v = V;
T->Left = T->Right = NULL;
T->flag = 0;
return T;
}
Tree Insert( Tree T, int V )
{
if ( !T )
T = NewNode(V);
else {
if ( V>T->v )
T->Right = Insert( T->Right, V );
else
T->Left = Insert( T->Left, V );
}
return T;
}
Tree MakeTree( int N )
{
Tree T;
int i, V;
scanf("%d", &V);
T = NewNode(V);
for (i=1; i<N; i++) {
scanf("%d", &V);
T = Insert(T, V);
}
return T;
}
int check ( Tree T, int V )
{
if ( T->flag ) {
if ( V<T->v )
return check(T->Left, V);
else if ( V>T->v )
return check(T->Right, V);
else
return 0;
}
else {
if ( V==T->v ) {
T->flag = 1;
return 1;
}
else
return 0;
}
}
int Judge( Tree T, int N )
{
int i, V, flag = 0;
/* flag: 0代表目前还一致，1代表已经不一致*/
scanf("%d", &V);
if ( V!=T->v )
flag = 1;
else
T->flag = 1;
for (i=1; i<N; i++) {
scanf("%d", &V);
if ( (!flag) && (!check(T, V)) )
flag = 1;
}
if (flag)
return 0;
else
return 1;
}
void ResetT ( Tree T ) /* 清除T中各结点的flag标记 */
{
if (T->Left) ResetT(T->Left);
if (T->Right) ResetT(T->Right);
T->flag = 0;
}
void FreeTree ( Tree T ) /* 释放T的空间 */
{
if (T->Left) FreeTree(T->Left);
if (T->Right) FreeTree(T->Right);
free(T);
}
int main()
{
int N, L, i;
Tree T;
scanf("%d", &N);
while (N) {
scanf("%d", &L);
T = MakeTree(N);
for (i=0; i<L; i++) {
if (Judge(T, N))
printf("Yes\n");
else
printf("No\n");
ResetT(T); /*清除T中的标记flag*/
}
FreeTree(T);
scanf("%d", &N);
}
return 0;
}
2、04-树5 Root of AVL Tree (25分)
Sample Input 1:
5
88 70 61 96 120
Sample Output 1:
70
Sample Input 2:
7
88 70 61 96 120 90 65
Sample Output 2:
88
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
typedef int ElementType;
typedef struct AVLNode *Position;
typedef Position AVLTree; /* AVL树类型 */
struct AVLNode{
ElementType Data; /* 结点数据 */
AVLTree Left; /* 指向左子树 */
AVLTree Right; /* 指向右子树 */
int Height; /* 树高 */
};
int Max ( int a, int b )
{
return a > b ? a : b;
}
int GetHeight(AVLTree A)
{
int MaxH, HR, HL;
if(A) {
HL = GetHeight(A->Left);
HR = GetHeight(A->Right);
MaxH = (HL>HR)?HL:HR;
return MaxH+1;
}
return -1;
}
AVLTree SingleLeftRotation(AVLTree A)
{
AVLTree B = A->Left;
A->Left = B->Right;
B->Right = A;
A->Height = Max(GetHeight(A->Left), GetHeight(A->Right)) + 1;
B->Height = Max(GetHeight(B->Left), A->Height) + 1;
return B;
}
AVLTree SingleRightRotation(AVLTree A)
{
AVLTree B = A->Right;
A->Right = B->Left;
B->Left = A;
A->Height = Max(GetHeight(A->Left), GetHeight(A->Right)) + 1;
A->Height = Max(GetHeight(B->Right), A->Height) + 1;
return B;
}
AVLTree DoubleLeftRightRotation(AVLTree A)
{
A->Left = SingleRightRotation(A->Left);
return SingleLeftRotation(A);
}
AVLTree DoubleRightLeftRotation(AVLTree A)
{
A->Right = SingleLeftRotation(A->Right);
return SingleRightRotation(A);
}
AVLTree Insert( AVLTree T, ElementType X )
{ /* 将X插入AVL树T中，并且返回调整后的AVL树 */
if ( !T ) { /* 若插入空树，则新建包含一个结点的树 */
T = (AVLTree)malloc(sizeof(struct AVLNode));
T->Data = X;
T->Height = 0;
T->Left = T->Right = NULL;
} /* if (插入空树) 结束 */
else if ( X < T->Data ) {
/* 插入T的左子树 */
T->Left = Insert( T->Left, X);
/* 如果需要左旋 */
if ( GetHeight(T->Left)-GetHeight(T->Right) == 2 )
if ( X < T->Left->Data )
T = SingleLeftRotation(T); /* 左单旋 */
else
T = DoubleLeftRightRotation(T); /* 左-右双旋 */
} /* else if (插入左子树) 结束 */
else if ( X > T->Data ) {
/* 插入T的右子树 */
T->Right = Insert( T->Right, X );
/* 如果需要右旋 */
if ( GetHeight(T->Left)-GetHeight(T->Right) == -2 )
if ( X > T->Right->Data )
T = SingleRightRotation(T); /* 右单旋 */
else
T = DoubleRightLeftRotation(T); /* 右-左双旋 */
} /* else if (插入右子树) 结束 */
/* else X == T->Data，无须插入 */
/* 别忘了更新树高 */
T->Height = Max( GetHeight(T->Left), GetHeight(T->Right) ) + 1;
return T;
}
int main()
{
int N, i;
ElementType t;
AVLTree T=NULL;
scanf("%d", &N);
for (i=0; i<N; i++) {
scanf("%d",&t);
T= Insert(T,t);
}
if(T)
printf("%d", T->Data);
return 0;
}
3、04-树6 Complete Binary Search Tree (30分)
Sample Input:
10
1 2 3 4 5 6 7 8 9 0
Sample Output:
6 3 8 1 5 7 9 0 2 4
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
int arr[1000], rearr[1000];
int compare( const void* a, const void* b ){
return *(int*)a - *(int*)b;
}
int getLeftLength(int n){ //利用二叉树的性质：满二叉树第i层有 2^(i-1) 个结点， 高为h的满二叉树有 2^h - 1 个结点（从1开始）
double h, x, L, t;
h = (double)(int)( log((double)n+1) / log(2.0) );
//h = floor( log((double)n+1) / log(2.0) );
x = n - pow(2.0, h) + 1 ;
t = pow(2.0, h - 1.0);
x = x < t ? x : t;
L = t - 1 + x;
return (int)L;
}
void solve( int left, int right, int root ){
//初始调用： solve(0, n-1, 0);
int n, L, leftRoot, rightRoot;
n = right - left + 1; //数组中的总个数
if(n == 0) return ; //递归退出的条件
L = getLeftLength(n); //计算出左子树的结点
rearr[root] = arr[left + L]; //将新的根结点放入新的数组
leftRoot = root * 2 + 1; //左孩子
rightRoot = leftRoot + 1; //右孩子
solve(left, left + L - 1, leftRoot);
solve(left + L + 1, right, rightRoot);
}
int main(){
int n;
scanf("%d", &n);
for(int i = 0; i < n; i++){
scanf("%d", &arr[i]);
}
qsort(arr, n, sizeof(int), compare);
solve(0, n-1, 0);
for(int i = 0; i < n; i++){
if( i != 0 ) printf(" ");
printf("%d", rearr[i]);
}
system("pause");
return 0;
}
4、04-树7 二叉搜索树的操作集 (30分)
#include <stdio.h>
#include <stdlib.h>
typedef int ElementType;
typedef struct TNode *Position;
typedef Position BinTree;
struct TNode{
ElementType Data;
BinTree Left;
BinTree Right;
};
void PreorderTraversal( BinTree BT ); /* 先序遍历，由裁判实现，细节不表 */
void InorderTraversal( BinTree BT ); /* 中序遍历，由裁判实现，细节不表 */
BinTree Insert( BinTree BST, ElementType X );
BinTree Delete( BinTree BST, ElementType X );
Position Find( BinTree BST, ElementType X );
Position FindMin( BinTree BST );
Position FindMax( BinTree BST );
int main()
{
BinTree BST, MinP, MaxP, Tmp;
ElementType X;
int N, i;
BST = NULL;
scanf("%d", &N);
for ( i=0; i<N; i++ ) {
scanf("%d", &X);
BST = Insert(BST, X);
}
printf("Preorder:"); PreorderTraversal(BST); printf("\n");
MinP = FindMin(BST);
MaxP = FindMax(BST);
scanf("%d", &N);
for( i=0; i<N; i++ ) {
scanf("%d", &X);
Tmp = Find(BST, X);
if (Tmp == NULL) printf("%d is not found\n", X);
else {
printf("%d is found\n", Tmp->Data);
if (Tmp==MinP) printf("%d is the smallest key\n", Tmp->Data);
if (Tmp==MaxP) printf("%d is the largest key\n", Tmp->Data);
}
}
scanf("%d", &N);
for( i=0; i<N; i++ ) {
scanf("%d", &X);
BST = Delete(BST, X);
}
printf("Inorder:"); InorderTraversal(BST); printf("\n");
return 0;
}
/* 你的代码将被嵌在这里 */
输入样例：
10
5 8 6 2 4 1 0 10 9 7
5
6 3 10 0 5
5
5 7 0 10 3
输出样例：
Preorder: 5 2 1 0 4 8 6 7 10 9
6 is found
3 is not found
10 is found
10 is the largest key
0 is found
0 is the smallest key
5 is found
Not Found
Inorder: 1 2 4 6 8 9
BinTree Insert( BinTree BST, ElementType X ){
if( !BST ){
BST = (BinTree)malloc(sizeof(struct TNode));
BST->Data = X;
BST->Left = BST->Right = NULL;
}
else {
if( X < BST->Data ) BST->Left = Insert( BST->Left, X );
else if( X > BST->Data ) BST->Right = Insert( BST->Right, X );
//else if(X = BST->Data) do nothing
}
return BST;
}
BinTree Delete( BinTree BST, ElementType X ){
Position TMP;
if( !BST ) printf("Not Found\n");
else {
if( X < BST->Data ) BST->Left = Delete( BST->Left, X ); //从左子树递归删除
else if( X > BST->Data ) BST->Right = Delete( BST->Right, X ); //从右子树递归删除
else { //BST就是要删除的结点
if( BST->Left && BST->Right ){ //如果BST左右孩子都有
TMP = FindMin( BST->Right ); //从右子树中找到最小的结点来代替该结点
BST->Data = TMP->Data;
BST->Right = Delete( BST->Right, BST->Data ); //从右子树中把最小的结点删除
}
else {
TMP = BST;
if( !BST->Left ) //如果只有右结点，或者没有结点
BST = BST->Right;
else //只有左结点
BST = BST->Left;
free( TMP );
}
}
}
return BST;
}
Position Find( BinTree BST, ElementType X ){
if( !BST ) return NULL;
else if( X == BST->Data ) return BST;
else if( X > BST->Data ) return Find( BST->Right, X );
else if( X < BST->Data ) return Find( BST->Left, X );
return NULL;
}
//递归查找最小元素
Position FindMin( BinTree BST ){
if( !BST ) return NULL;
else if( !BST->Left ) return BST;
else if( BST->Left ) FindMin( BST->Left );
}
//非递归查找最大元素
Position FindMax( BinTree BST ){
if( BST )
while( BST->Right ) BST = BST->Right;
return BST;
}
总结
简单总结下这周的学习内容，继续二叉树，我觉得自己非常有做调包侠的前途！！！
