剑指Offer37 二叉树深度与平衡二叉树判断

Posted 2020-08-06 Juntaran

  1 /*************************************************************************
  2     > File Name: 37_TreeDepth.cpp
  3     > Author: Juntaran
  4     > Mail: [email protected]
  5     > Created Time: 2016年09月03日 星期六 09时49分38秒
  6  ************************************************************************/
  7 
  8 #include <stdio.h>
  9 #include <malloc.h>
 10 #include <math.h>
 11 
 12 // 二叉树结构体
 13 struct BinaryTree
 14 {
 15     int val;
 16     struct BinaryTree* left;
 17     struct BinaryTree* right;
 18 };
 19 
 20 BinaryTree* createTree()
 21 {
 22     BinaryTree* root = (BinaryTree*)malloc(sizeof(BinaryTree));
 23     root->val = 1;
 24     root->left = (BinaryTree*)malloc(sizeof(BinaryTree));
 25     root->left->val = 2;
 26     root->right = (BinaryTree*)malloc(sizeof(BinaryTree));
 27     root->right->val = 3;
 28     root->left->left = (BinaryTree*)malloc(sizeof(BinaryTree));
 29     root->left->left->val = 4;
 30     root->left->left->left = NULL;
 31     root->left->left->right = NULL;
 32     root->left->right = (BinaryTree*)malloc(sizeof(BinaryTree));
 33     root->left->right->val = 5;
 34     root->left->right->right = NULL;
 35     root->left->right->left = (BinaryTree*)malloc(sizeof(BinaryTree));
 36     root->left->right->left->val = 7;
 37     root->left->right->left->left = NULL;
 38     root->left->right->left->right = NULL;
 39     root->right->right = (BinaryTree*)malloc(sizeof(BinaryTree));
 40     root->right->right->val = 6;
 41     root->right->left = NULL;
 42     root->right->right->left = NULL;
 43     root->right->right->right = NULL;
 44     // root->right->right->right = (BinaryTree*)malloc(sizeof(BinaryTree));
 45     // root->right->right->right->val = 8;
 46     // root->right->right->right->left = root->right->right->right->right = NULL;
 47     
 48     return root;
 49 }
 50 
 51 // 二叉树中序遍历
 52 void InOrder(BinaryTree* root)
 53 {
 54     if (root == NULL)
 55         return;
 56     
 57     InOrder(root->left);
 58     printf("%d ", root->val);
 59     InOrder(root->right);
 60 }
 61 
 62 // 二叉树的深度
 63 int TreeDepth(BinaryTree* root)
 64 {
 65     if (root == NULL)
 66         return 0;
 67     
 68     int left  = TreeDepth(root->left);
 69     int right = TreeDepth(root->right);
 70     
 71     return (left>right) ? (left+1) : (right+1);
 72 }
 73 
 74 // 判断一棵树是不是平衡二叉树
 75 bool isBalanced(BinaryTree* root)
 76 {
 77     if (root == NULL)
 78         return true;
 79     
 80     int left  = TreeDepth(root->left);
 81     int right = TreeDepth(root->right);
 82     
 83     int diff = abs(left - right);
 84     if (diff > 1)
 85         return false;
 86     
 87     return isBalanced(root->left) && isBalanced(root->right);
 88 }
 89 
 90 // 后序遍历方法
 91 bool isBalanced2(BinaryTree* root, int* depth)
 92 {
 93     if (root == NULL)
 94     {
 95         *depth = 0;
 96         return true;
 97     }
 98     int left, right;
 99     if (isBalanced2(root->left, &left) && isBalanced2(root->right, &right))
100     {
101         int diff = abs(left - right);
102         if (diff <= 1)
103         {
104             *depth = 1 + (left>right ? left : right);
105             return true;
106         }
107     }
108     return false;
109 }
110 
111 bool isBalanced2(BinaryTree* root)
112 {
113     int depth = 0;
114     return isBalanced2(root, &depth);
115 }
116 
117 
118 
119 int main()
120 {
121     BinaryTree* test = createTree();
122     InOrder(test);
123     int depth = TreeDepth(test);
124     printf("\ndepth is %d\n", depth);
125     if (isBalanced2(test) == true)
126         printf("Balance\n");
127     else
128         printf("No Balance\n");
129     
130 }