题解 | #农场最大产奶牛群#

/**
 * struct TreeNode {
 *  int val;
 *  struct TreeNode *left;
 *  struct TreeNode *right;
 * };
 */
/**
 * 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
 */
#include <stdio.h>
void getMaxResult(struct TreeNode* root, int sum, int* max) {
    if (!root) return;
    if (root->left == NULL && root->right == NULL) {
        sum += root->val;
        (*max) = fmax((*max), sum);
    }
    getMaxResult(root->left, sum + root->val, max);
    getMaxResult(root->right, sum + root->val, max);
}
int  dfs(struct TreeNode* root) {
    if (!root) return 0;
    int left = 0, right = 0;
    getMaxResult(root->left, 0, &left);
    getMaxResult(root->right, 0, &right);
    return root->val + left + right;
}
void get(struct TreeNode* root, int* max) {
    if (!root) return;
    int num = dfs(root);
    (*max) = fmax((*max), num);
    get(root->left, max);
    get(root->right, max);
}
int maxMilkSum(struct TreeNode* root ) {
    int max = -1;
    get(root, &max);
    return max;
}