Leetcode-Solutions/FindBottomLeftTreeValue.cpp at main · jasonpyau/Leetcode-Solutions · GitHub

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/**
 * 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 findBottomLeftValue(TreeNode* root) {
        queue<TreeNode*> q;
        q.push(root);
        int ans = 0;
        while (!q.empty()) {
            ans = q.front()->val;
            for (int i = 0, size = q.size(); i < size; ++i) {
                TreeNode* curr = q.front();
                q.pop();
                if (curr->left) {
                    q.push(curr->left);
                }
                if (curr->right) {
                    q.push(curr->right);
                }
            }
        }
        return ans;
    }
};