/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public int minDepth(TreeNode root) {
LinkedList<Pair<TreeNode,Integer>> ans = new LinkedList<>();
if(root == null){
return 0;
}
else{
ans.add(new Pair<>(root,1));
}
int depth = 0;
while(!ans.isEmpty()){
Pair<TreeNode,Integer> cur = ans.poll();
TreeNode r = cur.getKey();
depth = cur.getValue();
if(r.left == null && r.right == null){
break;
}
if(r.left != null){
ans.add(new Pair<>(r.left, depth + 1));
}
if(r.right != null){
ans.add(new Pair<>(r.right,depth + 1));
}
}
return depth;
}
}
