1.二叉树的前序遍历
2.二叉树的中序遍历
3.二叉树的后序遍历
4.二叉树的层序遍历
5.二叉树的节点个位
6.二叉树的叶子节点个位数
7.二叉树的的k层节点数
8.查找值为x的节点
9.二叉树的销毁
10.判断二叉树是否为完全二叉树
11.求二叉树的高度h
12.通过前序遍历构建二叉树
#include<stdio.h> #include<stdlib.h> #include<assert.h> #include<stdbool.h> typedef int BTDataType; typedef struct BinaryTreeNode { BTDataType data; struct BinaryTreeNode* left; struct BinaryTreeNode* right; }BTNode; BTNode* BuyNode(BTDataType x); BTNode* CreatBinaryTree(); void BTreeDestory(BTNode* root); int BinaryTreeSize(BTNode* root); int BinaryTreeLeafSize(BTNode* root); int BinaryTreeLevelKSize(BTNode* root, int k); //查找值为x的节点 BTNode* BinaryTreeFind(BTNode* root, BTDataType x); //前、中、后序遍历 void PrevOrder(BTNode* root); void InOrder(BTNode* root); void PostOrder(BTNode* root); //层序遍历 void LevelOrder(BTNode* root); bool BinaryTreeComplete(BTNode* root); //通过前序遍历构建二叉树 BTNode* PrevOrderCreate(char* a, int* pi);
1.通过前序遍历构建二叉树
BTNode* BuyNode(BTDataType x) { BTNode* node = (BTNode*)malloc(sizeof(BTNode)); if (node == NULL) { perror("malloc fail"); return NULL; } node->data = x; node->left = NULL; node->right = NULL; return node; } //（int* pi）是数组的下标用来遍历数组，因为如果不传地址，形参改变不会影响实参 BTNode* PrevOrderCreate(char* a, int* pi) { if (a[*pi] == '#') { ++(*pi); return NULL; } BTNode* root = BuyNode(a[*pi]); ++(*pi); //递归 root->left = PrevOrderCreate(a, pi); root->right = PrevOrderCreate(a, pi); return root; }
2. 二叉树的销毁
void BTreeDestory(BTNode* root) { if (root == NULL) return; BTreeDestory(root->left); BTreeDestory(root->right); free(root); }
3.二叉树的遍历
//前序遍历 void PrevOrder(BTNode* root) { if (root == NULL) { printf("N "); return; } printf("%d ", root->data); PrevOrder(root->left); PrevOrder(root->right); } //中序遍历 void InOrder(BTNode* root) { if (root == NULL) { printf("N "); return; } InOrder(root->left); printf("%d ", root->data); InOrder(root->right); } //后序遍历 void PostOrder(BTNode* root) { if (root == NULL) { printf("N "); return; } PostOrder(root->left); PostOrder(root->right); printf("%d ", root->data); } //层序遍历 void LevelOrder(BTNode* root) { Queue q; QueueInit(&q); if (root) QueuePush(&q, root); while (!QueueEmpty(&q)) { BTNode* front = QueueFront(&q); QueuePop(&q); printf("%d ", front->data); if (front->left) QueuePush(&q, front->left); if (front->right) QueuePush(&q, front->right); } printf("\n"); QueueDestroy(&q); }层序遍历需要用到队列： 队列的实现_元清加油的博客-CSDN博客
4. 二叉树的节点个位和二叉树的叶子节点个位数
二叉树的节点个位 int BinaryTreeSize(BTNode* root) { return root == NULL ? 0 : BinaryTreeSize(root->left) + BinaryTreeSize(root->right) + 1; } 二叉树的叶子节点个位数 int BinaryTreeLeafSize(BTNode* root) { if (root == NULL) { return 0; } if (root->left == NULL && root->right == NULL) { return 1; } return BinaryTreeLeafSize(root->left) + BinaryTreeLeafSize(root->right); }
5. 二叉树的的k层节点数和查找值为x的节点
二叉树的的k层节点数 int BinaryTreeLevelKSize(BTNode* root, int k) { assert(k > 0); if (root == NULL) return 0; if (k == 1) return 1; return BinaryTreeLevelKSize(root->left, k - 1) + BinaryTreeLevelKSize(root->right, k - 1); } 查找值为x的节点 BTNode* BinaryTreeFind(BTNode* root, BTDataType x) { if (root == NULL) return NULL; if (root->data == x) return root; BTNode* ret1 = BinaryTreeFind(root->left, x); if (ret1) return ret1; BTNode* ret2 = BinaryTreeFind(root->right, x); if (ret2) return ret2; return NULL; }
6. 判断二叉树是否为完全二叉树和求二叉树的高度h
// 判断二叉树是否是完全二叉树 bool BinaryTreeComplete(BTNode* root) { Queue q; QueueInit(&q); if (root) QueuePush(&q, root); while (!QueueEmpty(&q)) { BTNode* front = QueueFront(&q); QueuePop(&q); // 遇到空就跳出 if (front == NULL) break; QueuePush(&q, front->left); QueuePush(&q, front->right); } // 检查后面的节点有没有非空 // 有非空，不是完全二叉树 while (!QueueEmpty(&q)) { BTNode* front = QueueFront(&q); QueuePop(&q); if (front) { QueueDestroy(&q); return false; } } QueueDestroy(&q); return true; } //求二叉树的高度h int BinaryTreeHeight(BTNode* root) { if (root == NULL) { return 0; } int LeftHeight = BinaryTreeHeight(root->left); int RightHeight = BinaryTreeHeight(root->right); return LeftHeight > RightHeight ? LeftHeight + 1 : RightHeight + 1; }判断是否为完全二叉树需要用到队列： 队列的实现_元清加油的博客-CSDN博客