110. Balanced Binary Tree
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
bool flag=true;
int dfs(TreeNode*node,int depth){
if(node==nullptr)return 0;
int left=dfs(node->left,depth+1);
int right=dfs(node->right,depth+1);
if(abs(left-right)>1)flag=false;
return max(left,right)+1;
}
public:
bool isBalanced(TreeNode* root) {
int a=dfs(root,0);
return flag;
}
};
257. All Paths of a Binary Tree
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
vector<string>res;
void travesal(TreeNode* root,vector<int>&vec){
if(root->left==nullptr&&root->right==nullptr){
string s;
for(int i=0;i<vec.size();i++){
if(i!=vec.size()-1){
s+=to_string(vec[i])+"->";
}else{
s+=to_string(vec[i]);
}
}
res.push_back(s);
return;
}
if(root->left!=nullptr){
vec.push_back(root->left->val);
travesal(root->left,vec);
vec.pop_back();
}
if(root->right!=nullptr){
vec.push_back(root->right->val);
travesal(root->right,vec);
vec.pop_back();
}
}
public:
vector<string> binaryTreePaths(TreeNode* root) {
vector<int>vec;
vec.push_back(root->val);
travesal(root,vec);
return res;
}
};
404. The sum of the left leaves
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
int res=0;
void travesal(TreeNode* root,bool isleft){
if(root->left==nullptr&&root->right==nullptr&&isleft){
res+=root->val;
return ;
}
if(root->left!=nullptr)travesal(root->left,true);
if(root->right!=nullptr)travesal(root->right,false);
}
public:
int sumOfLeftLeaves(TreeNode* root) {
travesal(root,false);
return res;
}
};