LeetCode刷题笔记-112.路径总和

C语言

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */

bool dfs(struct TreeNode *t, int val, int target) {
    bool bl = false;
    bool br = false;
    
    if(t == NULL) {
        return val == target;
    }
    if(t->left == NULL && t->right == NULL) {
        return (t->val + val) == target;
    }
    if (t->left != NULL) {
        bl = dfs(t->left, t->val + val, target);
    }
    if (t->right != NULL) {
        br = dfs(t->right, t->val + val, target);
    }
    return bl | br;
}
bool hasPathSum(struct TreeNode* root, int targetSum){
    if(root == NULL) //注意点1:当根为空返回false
        return false;
    return dfs(root, 0, targetSum);
}

注意点

1. 当根节点为空时，返回false;

结果

题目