計算二叉樹的深度+判斷二叉樹是否是平衡二叉樹

計算二叉樹的深度

/*
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};*/
class Solution {
public:
    int TreeDepth(TreeNode* pRoot)
    {
        if(pRoot==NULL)
            return 0;
        int left  = TreeDepth(pRoot->left);
        int right = TreeDepth(pRoot->right);
        return left>right?left+1:right+1;
    }
};

判斷二叉樹是否是平衡二叉樹

class Solution {
public:
    int TreeDepth(TreeNode* pRoot){
        if(pRoot==NULL)
            return 0;
        int left = TreeDepth(pRoot->left);
        int right = TreeDepth(pRoot->right);
        return left>right?left+1:right+1;
    }
    bool IsBalanced_Solution(TreeNode* pRoot) {
        if(pRoot==NULL)
            return true;
        int left = TreeDepth(pRoot->left);
        int right = TreeDepth(pRoot->right);
        if(left-right>1||left-right<-1)
            return false;
        return IsBalanced_Solution(pRoot->left)&&IsBalanced_Solution(pRoot->right);
    }
};

//後續遍歷二叉樹，遍歷過程中求子樹高度，判斷是否平衡
class Solution {
public:
    bool IsBalanced(TreeNode *root, int & dep){
        if(root == NULL){
            return true;
        }
        int left = 0;
        int right = 0;
        if(IsBalanced(root->left,left) && IsBalanced(root->right, right)){
            int dif = left - right;
            if(dif<-1 || dif >1)
                return false;
            dep = (left > right ? left : right) + 1;
            return true;
        }
        return false;
    }
    bool IsBalanced_Solution(TreeNode* pRoot) {
        int dep = 0;
        return IsBalanced(pRoot, dep);
    }
};