【树】leetcode_513_找树左下角的值

【树】leetcode_513_找树左下角的值

/**
 * 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) {
        
        TreeNode *cur = root;
        queue<TreeNode *> q_node;

        q_node.push(cur);
        TreeNode *re;

        while(!q_node.empty()){
            int s= q_node.size();
            for(int i = 0; i<s; i++){
                if (i == 0){
                    re = q_node.front();
                }
                cur = q_node.front();
                
                q_node.pop();
                if (cur->left) {q_node.push(cur->left);}
                if (cur->right) {q_node.push(cur->right);}



            }
        }
        return re->val;

    }
};