270. Closest Binary Search Tree Value

    
    /*
     * 270. Closest Binary Search Tree Value
     * 2016-6-25 by Mingyang
     */
      public int closestValue(TreeNode root, double target) {
            int closest = root.val;  
            double min = Double.MAX_VALUE;  
            while(root!=null) {  
                if( Math.abs(root.val - target) < min  ) {  
                    min = Math.abs(root.val - target);  
                    closest = root.val;  
                }                
                if(target < root.val) {  
                    root = root.left;  
                } else if(target > root.val) {  
                    root = root.right;  
                } else {  
                    return root.val;  
                }  
            }            
            return closest;  
        }