[LeetCode] Minimum Depth of Binary Tree

https://leetcode.com/problems/minimum-depth-of-binary-tree/

Minimum Depth of Binary Tree - LeetCode

이진 트리에서 최소 깊이를 가진 leaf node의 depth를 구하는 문제이다. 기본적인 BFS 문제라고 생각한다.

/**
 * 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 minDepth(TreeNode* root) {
        if(root==nullptr)
            return 0;
        int index=0;
        queue<TreeNode*> q;
        vector<int> d;
        d.push_back(1);
        q.push(root);
        while(!q.empty()) {
            TreeNode* temp = q.front();
            q.pop();
            if(temp->right==nullptr && temp->left==nullptr)
                return d[index];
            if(temp->right!=nullptr) {
                q.push(temp->right);
                d.push_back(d[index]+1);
            }
            if(temp->left!=nullptr) {
                q.push(temp->left);
                d.push_back(d[index]+1);
            }
            index++;
        }
        return d[index];
    }
};