Easy to Understand Java Solution

'''

class Solution {

public int minDepth(TreeNode root) {

if(root == null)

return 0;

int left = minDepth(root.left);

int right = minDepth(root.right);

if(left == 0 && right == 0)

return 1;

if(left == 0)

left = Integer.MAX_VALUE;

if(right == 0)

right = Integer.MAX_VALUE;

right = Integer.MAX_VALUE;

return Math.min(left,right)+1;

}

}

'''