思路:根據題目定義,子樹的高度差超過1即爲不平衡,所以可以寫一個求子樹高度的函數,用遞歸實現比較方便
/*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};*/
class Balance {
public:
int getHeight(TreeNode* node){
if(node==NULL)
return 0;
else
return getHeight(node->left)>getHeight(node->right)?getHeight(node->left)+1:getHeight(node->right)+1;
}
bool isBalance(TreeNode* root) {
// write code here
if(root==NULL)
return true;
int heightDiff = getHeight(root->left)-getHeight(root->right);
if(heightDiff<-1 || heightDiff>1)
return false;
else
return (isBalance(root->left) && isBalance(root->right));
}
};