C language converts arrays into binary trees

2021/12/9 Today is my first blog , Because on the way of learning programming , With the guidance of big bloggers, you can eliminate all kinds of problems step by step , Report an attitude of gratitude , Continue their will . secondly , I want to provide a little reference for those beginners . Most important , By the way, strengthen your understanding of knowledge points . I hope I can keep on , Be able to help people who are eager to make progress . If there are some problems in the content, please correct .                                                        ——HDU Tu Yisheng （aka Kuang Kuang ）

#include<stdio.h>
#include<stdlib.h>
#include<time.h>

int a[21];// The data is in 21 Within a 
int DataCount = 0;

typedef struct BiNode{
	int data;
	struct BiNode *lchild;
	struct BiNode *rchild;
}*BiTree,BiTNode;

BiTree T = NULL;

// Create a random dataset 
void create_data(int MaxData){
	int i,j;
	srand(time(NULL));
	for(i=0;i<DataCount;i++){
		a[i] = rand()%MaxData;
		for(j=0;j<i;j++){
			if(a[j]==a[i]){
				a[i] = rand()%MaxData;
				j=-1;
			}
		}
	}
}

//  Create a binary tree 
void create(BiTree Troot,int cnt){
	BiTree Nodep;
	if(cnt==DataCount){
		return ;
	}
	Nodep = (BiTree)malloc(sizeof(BiTNode));
	Nodep->data = a[cnt];
	Nodep->lchild = NULL;
	Nodep->rchild = NULL;
	if(Troot == NULL){
		T = Nodep;
		create(T,++cnt);
	}
	else if(Nodep->data<=Troot->data){
		if(Troot->lchild==NULL){
			Troot->lchild = Nodep;
			create(T,++cnt);
		}
		else{
			create(Troot->lchild,cnt);
		}
	}
	else if(Nodep->data>Troot->data){
		if(Troot->rchild == NULL){
			Troot->rchild = Nodep;
			create(T,++cnt);
		}
		else{
			create(Troot->rchild);
        }
    }
}

// In the sequence traversal 
void inOrder(BiTree T){
	if(T){	
		inOrder(T->lchild);
		printf("%d ",T->data);
		inOrder(T->rchild);
	}
}


int main(){
	int i;
	int MaxData;
	printf("DataCount:");
	scanf("%d",&DataCount);
	printf("MaxData:");
	scanf("%d",&MaxData);
	create_data(MaxData);
	printf(" Raw data ：");
	for(i=0;i<DataCount;i++){
		printf("%d ",a[i]);
	}
	printf("\n");
	create(T,0);
    inOrder(T);
	return 0;
}

First , Anyone who can search this blog should know the definition of binary tree , I won't go into details here . Build a binary tree , First of all, there must be a structure variable to store data and the addresses of the left child and the right child .

typedef struct BiNode{
        int data;
        struct BiNode *lchild;
        struct BiNode *rchild;
}*BiTree,BiTNode;  // Self defined data types ,BiTree Is a pointer ,BiTNode Is the data structure type .

  after , We are going to generate a containing n An unequal array of elements .

// Create a random dataset
void create_data(int MaxData,int arr[],int DataCount){
        int i,j;
        srand(time(NULL));  // Random seeds
        for(i=0;i<DataCount;i++){
                arr[i] = rand()%MaxData;  arr[i] -> (0,MaxData)
                for(j=0;j<i;j++){
                        if(arr[j]==arr[i]){
                                arr[i] = rand()%MaxData;
                                j=-1;
                        }
                }
        }
}

  With the initial array , We can build a binary tree .

// Create a binary tree
void create(BiTree Troot,int cnt){  // Don't return the pointer as a binary tree, there will be problems .
        BiTree Nodep;
        if(cnt==DataCount){
                return ;
        }
        Nodep = (BiTree)malloc(sizeof(BiTNode));
        Nodep->data = a[cnt];
        Nodep->lchild = NULL;
        Nodep->rchild = NULL;
        if(Troot == NULL){
                T = Nodep; // initialization
                create(T,++cnt);
        }
        else if(Nodep->data<=Troot->data){
                if(Troot->lchild==NULL){
                        Troot->lchild = Nodep;
                        create(T,++cnt);
                }
                else{
                        create(Troot->lchild,cnt);
                }
        }
        else if(Nodep->data>Troot->data){
                if(Troot->rchild == NULL){
                        Troot->rchild = Nodep;
                        create(T,++cnt);
                }
                else{
                        create(Troot->rchild,cnt);
                }
        }
}
 

  Finally, we will output the result of the middle order traversal .

// In the sequence traversal
void inOrder(BiTree T){
    if(T){    
        inOrder(T->lchild);
        printf("%d ",T->data);
        inOrder(T->rchild);
    }
}