Find Bottom Left Tree Value
Problem Statement - link #
Given the root of a binary tree, return the leftmost value in the last row of the tree.
Examples #
Example 1:
Input: root = [2,1,3]
Output: 1
Example 2:
Input: root = [1,2,3,4,null,5,6,null,null,7]
Output: 7
Constraints #
- The number of nodes in the tree is in the range
[1, 10^5] -2^31 <= Node.val <= 2^31 - 1
Solutions #
/**
* 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 {
public:
int deepR,deepC,res;
void helper(TreeNode* root, int r, int c){
if(root==NULL) return;
if(r>deepR) { deepR=r; deepC=c; res = root->val;}
else if (r==deepR && c < deepC) {deepC=c; res = root->val;}
helper(root->left,r+1,c-1);
helper(root->right,r+1,c+1);
}
int findBottomLeftValue(TreeNode* root) {
deepR=deepC=0;
res = root->val;
helper(root,deepR,deepC);
return res;
}
};