Week Training: 513 Find Bottom Left Tree Value

最新推荐文章于 2025-07-02 11:31:15 发布

richard978

最新推荐文章于 2025-07-02 11:31:15 发布

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本文链接：https://blog.youkuaiyun.com/richard978/article/details/69808690

本文介绍了一种使用广度优先搜索(BFS)来查找二叉树最后一行最左边节点值的方法。通过队列辅助，逐层遍历树，并更新返回值，最终得到底部最左侧的值。

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The purpose of this problem is to find the leftmost value in the last row of the tree, what first come to me is BFS. Using a queue for auxiliary, we traverse the tree row by row, finding the leftmost value of each row and update the returned value. Until the queue is empty, which means the whole tree has been visited, the last value is the leftmost value of the bottom row. The whole process is almost like that in BFS.

class Solution {
public:
    int findBottomLeftValue(TreeNode* root) {
        if(root==NULL)
            return 0;
        int Lvalue = 0;
        queue<TreeNode*> q;
        q.push(root);
        while(!q.empty()){
            int size=q.size();
            for(int i=0;i<size;i++){
                TreeNode* TNode = q.front();
                q.pop();
                if(i==0) Lvalue = TNode->val;
                if(TNode->left) q.push(TNode->left);
                if(TNode->right) q.push(TNode->right);
            }
        }
        return Lvalue;
    }
};