1302. Deepest Leaves Sum - medium
문제
Given a binary tree, return the sum of values of its deepest leaves.
제한사항
- The number of nodes in the tree is between 1 and 10^4.
- The value of nodes is between 1 and 100.
입출력 예
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Input: root = [1,2,3,4,5,null,6,7,null,null,null,null,8]
Output: 15
풀이
- Tree, DFS
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/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int deepestLeavesSum(TreeNode* root) {
map<int, int> sumMap;
stack<pair<TreeNode*, int>> s;
s.push({root, 0});
// DFS로 트리의 깊이별 노드의 val값 합을 구함
while(!s.empty()){
auto node = s.top();
s.pop();
// 깊이별 합을 map에 저장
// sumMap[현재 노드의 깊이] += 현재 노드의 값
sumMap[node.second] += node.first->val;
if(node.first->right){
s.push({node.first->right, node.second + 1});
}
if(node.first->left){
s.push({node.first->left, node.second + 1});
}
}
return sumMap.rbegin()->second;
}
};