[LeetCode] [Medium] [JS] 1315. Sum of Nodes with Even-Valued Grandparent

 

1. 문제

 

Given a binary tree, return the sum of values of nodes with even-valued grandparent.  (A grandparent of a node is the parent of its parent, if it exists.)

If there are no nodes with an even-valued grandparent, return 0.

 

 

 

2. 예시

 

 

Input: root = [6,7,8,2,7,1,3,9,null,1,4,null,null,null,5]
Output: 18
Explanation: The red nodes are the nodes with even-value grandparent while the blue nodes are the even-value grandparents.

 

 

 

3. 풀이

 

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number}
 */
var sumEvenGrandparent = function(root) {
    let result = 0;
    let trav = function(node, pa, gpa) {
        if(!node) return;
        if(gpa && gpa%2 === 0){
            result += node.val;
        }
        gpa = pa;
        pa = node.val;
        trav(node.left, pa, gpa);
        trav(node.right, pa, gpa);
    };
    trav(root, null, null);
    return result;
};

 

 

 

4. 결과

 

14 / 14 test cases passed.
Status: Accepted
Runtime: 84 ms
Memory Usage: 42.8 MB