二叉排序树、二叉查找树、删除

建树、中序遍历 

#include 
#include 
#include 

typedef int keyType;
typedef struct BSnode {
    keyType key;
    struct BSnode *left, *right;
} LBtree, *Btree;

int Binsert(Btree &tree, int num) {
    Btree bNew = (Btree) calloc(1, sizeof(LBtree));
    bNew->key = num;
    if (tree == NULL) {
        tree = bNew;
        return 0;
    }
    Btree p, parent;//用来遍历
    p = tree;
    while (p) {
        parent = p;//父节点
        if (num > p->key) {
            p = p->right;
        } else if (num < p->key) {
            p = p->left;
        }
    }
    if (num > parent->key) {
        parent->right = bNew;
    } else {
        parent->left = bNew;
    }
    return 0;
}

void creatTree(Btree &tree, int *arr, int length) {
    for (int i = 0; i < length; i++) {
        Binsert(tree, arr[i]);
    }
}

void inOrder(Btree p) {
    if (p) {
        inOrder(p->left);
        printf("%3d", p->key);
        //递归
        inOrder(p->right);
    }
}

void searchTree(Btree tree, Btree &parent, int num) {
    parent = NULL;
    while (tree && tree->key != num) {
        parent = tree;
        if (num > tree->key) {
            tree = tree->right;
        } else if (num < tree->key) {
            tree = tree->left;
        }
    }
    printf("%d",tree->key);
}

int main() {
    Btree tree = NULL;//树根
    int arr[7] = {50, 20, 66, 40, 28, 79, 58};
    creatTree(tree, arr, 7);
//    inOrder(tree);
    Btree parent;
    searchTree(tree, parent, 28);
    return 0;
}

删除

#include 
#include 
#include 

typedef int keyType;
typedef struct BSnode {
    keyType key;
    struct BSnode *left, *right;
} LBtree, *Btree;

int Binsert(Btree &tree, int num) {
    Btree bNew = (Btree) calloc(1, sizeof(LBtree));
    bNew->key = num;
    if (tree == NULL) {
        tree = bNew;
        return 0;
    }
    Btree p, parent;//用来遍历
    p = tree;
    while (p) {
        parent = p;//父节点
        if (num > p->key) {
            p = p->right;
        } else if (num < p->key) {
            p = p->left;
        }
    }
    if (num > parent->key) {
        parent->right = bNew;
    } else {
        parent->left = bNew;
    }
    return 0;
}

void creatTree(Btree &tree, int *arr, int length) {
    for (int i = 0; i < length; i++) {
        Binsert(tree, arr[i]);
    }
}

void inOrder(Btree p) {
    if (p) {
        inOrder(p->left);
        printf("%3d", p->key);
        //递归
        inOrder(p->right);
    }
}

void searchTree(Btree tree, Btree &parent, int num) {
    parent = NULL;
    while (tree && tree->key != num) {
        parent = tree;
        if (num > tree->key) {
            tree = tree->right;
        } else if (num < tree->key) {
            tree = tree->left;
        }
    }
    printf("%d", tree->key);
}

void deleteNode(Btree &tree, int num) {
    if (tree == NULL) {
        return;
    }
    if (tree->key > num) {
        deleteNode(tree->left, num);
    } else if (tree->key < num) {
        deleteNode(tree->right, num);
    } else {
        if (tree->left == NULL) {
            Btree tem = tree;
            tree = tree->right;
            free(tem);
        } else if (tree->right == NULL) {
            Btree tem = tree;
            tree = tree->left;
            free(tem);
        } else {
            Btree tem = tree->left;
            while (tree->right) {
                tem = tree->right;
            }
            tree->key = tem->key;
            deleteNode(tree->left, tem->key);
        }
    }
}

int main() {
    Btree tree = NULL;//树根
    int arr[7] = {50, 20, 66, 40, 28, 79, 58};
    creatTree(tree, arr, 7);
//    inOrder(tree);
    Btree parent;
//    searchTree(tree, parent, 28);
    deleteNode(tree, 40);
    inOrder(tree);
    return 0;
}