Code & Func

第49天。

今天的题目是Maximum Level Sum of a Binary Tree:

送分题，直接用层次便利计算每一层的元素之和，然后去最大即可。

1
int maxLevelSum(TreeNode* root) {
2
    if (!root) return -1;
3

4
    int max_level = -1, max_sum = INT_MIN;
5

6
    queue<TreeNode *> q;
7
    q.push(root);
8

9
    int cur_level = 1, cur_sum;
10

11
    while(!q.empty()) {
12
        cur_sum = 0;
13
        for(int i = 0, size = q.size(); i < size; i++) {
14
            root = q.front(); q.pop();
15
            cur_sum += root->val;
12 collapsed lines
16
            if (root->left) q.push(root->left);
17
            if (root->right) q.push(root->right);
18
        }
19
        if (cur_sum > max_sum) {
20
            max_sum = cur_sum;
21
            max_level = cur_level;
22
        }
23
        cur_level++;
24
    }
25

26
    return max_level;
27
}