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
        if (root == nullptr) return 0;
        queue<TreeNode*> q;
        q.push(root);
        int max_sum = 0, level = 0;
        int level_c = 0;
        while (q.size()) {
            level_c++;
            int size = q.size();
            int sum = 0;
            for (int i = 0; i < size; i++) {
                TreeNode* t = q.front();
                sum += t->val;
                if (t->left) q.push(t->left);
                if (t->right) q.push(t->right);
                q.pop();
            }
            if (sum > max_sum) {
                level = level_c;
                max_sum = sum;
            } else if (sum == max_sum) {
                level = level_c;
            }
        }
        return level;
    }
};