题解 | #重量级的一层#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param root TreeNode类 
     * @return int整型
     */
    int maxLevelSum(TreeNode* root) {
        // write code here

        int ans = 0;
        int sum = 0;
        int high = 0;
        if(!root)
            return ans;


        queue<TreeNode*> q;
        q.push(root);

        while(!q.empty())
        {
            ++high;
            int len = q.size();
            int t = 0;
            for(int i=0; i<len; ++i)
            {
                TreeNode* r = q.front();
                q.pop();
                t += r->val;

                if(r->left)
                    q.push(r->left);
                if(r->right)
                    q.push(r->right);
            }
            
            if(t>=sum)
            {
                sum = t;
                ans = high;
            }
            
        }
        
        return ans;
    }
};