LeetCode题解之Find Bottom Left Tree Value

 1 int findBottomLeftValue(TreeNode* root) {
 2         if (root == NULL)
 3             return 0;
 4         queue<TreeNode*> q;
 5         q.push(root);
 6         
 7         int val = 0;
 8        while (!q.empty()) {
 9             int size = q.size();
10             for(int i = 0; i < size; i++) {
11                 TreeNode *node = q.front();
12                 if (node->left != NULL)
13                     q.push(node->left);
14                 if (node->right != NULL)
15                     q.push(node->right);
16                     
17                 
18                 if (i == 0)
19                    val = node->val;
20                 q.pop();
21             }
22         }
23         return val;
24     }